Merge github.com:grpc/grpc into hybrid

14 files changed, 305 insertions, 197 deletions

diff --git a/src/core/lib/channel/channel_args.c b/src/core/lib/channel/channel_args.c
index 3de31d99da..238d176dfa 100644
--- a/src/core/lib/channel/channel_args.c
+++ b/src/core/lib/channel/channel_args.c
@@ -31,17 +31,18 @@
  *
  */
 
-#include "src/core/lib/channel/channel_args.h"
-#include <grpc/grpc.h>
-#include "src/core/lib/support/string.h"
+#include <limits.h>
+#include <string.h>
 
 #include <grpc/compression.h>
+#include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
 
-#include <string.h>
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/support/string.h"
 
 static grpc_arg copy_arg(const grpc_arg *src) {
   grpc_arg dst;
@@ -330,7 +331,7 @@ const grpc_arg *grpc_channel_args_find(const grpc_channel_args *args,
 }
 
 int grpc_channel_arg_get_integer(const grpc_arg *arg,
-                                 grpc_integer_options options) {
+                                 const grpc_integer_options options) {
   if (arg == NULL) return options.default_value;
   if (arg->type != GRPC_ARG_INTEGER) {
     gpr_log(GPR_ERROR, "%s ignored: it must be an integer", arg->key);
diff --git a/src/core/lib/channel/channel_args.h b/src/core/lib/channel/channel_args.h
index 5ffcacb7fd..f0f603e251 100644
--- a/src/core/lib/channel/channel_args.h
+++ b/src/core/lib/channel/channel_args.h
@@ -120,9 +120,10 @@ typedef struct grpc_integer_options {
   int min_value;
   int max_value;
 } grpc_integer_options;
+
 /** Returns the value of \a arg, subject to the contraints in \a options. */
 int grpc_channel_arg_get_integer(const grpc_arg *arg,
-                                 grpc_integer_options options);
+                                 const grpc_integer_options options);
 
 bool grpc_channel_arg_get_bool(const grpc_arg *arg, bool default_value);
 
diff --git a/src/core/lib/channel/context.h b/src/core/lib/channel/context.h
index 2c1174ce7a..6c931ad28a 100644
--- a/src/core/lib/channel/context.h
+++ b/src/core/lib/channel/context.h
@@ -50,9 +50,6 @@ typedef enum {
   /// Reserved for traffic_class_context.
   GRPC_CONTEXT_TRAFFIC,
 
-  /// Costs for Load Reporting.
-  GRPC_CONTEXT_LR_COST,
-
   GRPC_CONTEXT_COUNT
 } grpc_context_index;
 
diff --git a/src/core/lib/iomgr/sockaddr_utils.h b/src/core/lib/iomgr/sockaddr_utils.h
index 2b22f11b49..be3ea2038f 100644
--- a/src/core/lib/iomgr/sockaddr_utils.h
+++ b/src/core/lib/iomgr/sockaddr_utils.h
@@ -50,7 +50,7 @@ int grpc_sockaddr_to_v4mapped(const grpc_resolved_address *addr,
                               grpc_resolved_address *addr6_out);
 
 /* If addr is ::, 0.0.0.0, or ::ffff:0.0.0.0, writes the port number to
-   *port_out (if not NULL) and returns true, otherwise returns false. */
+ *port_out (if not NULL) and returns true, otherwise returns false. */
 int grpc_sockaddr_is_wildcard(const grpc_resolved_address *addr, int *port_out);
 
 /* Writes 0.0.0.0:port and [::]:port to separate sockaddrs. */
diff --git a/src/core/lib/iomgr/udp_server.c b/src/core/lib/iomgr/udp_server.c
index 60579e18ba..ca283d034f 100644
--- a/src/core/lib/iomgr/udp_server.c
+++ b/src/core/lib/iomgr/udp_server.c
@@ -79,10 +79,15 @@ struct grpc_udp_listener {
   grpc_resolved_address addr;
   grpc_closure read_closure;
   grpc_closure write_closure;
+  // To be called when corresponding QuicGrpcServer closes all active
+  // connections.
+  grpc_closure orphan_fd_closure;
   grpc_closure destroyed_closure;
   grpc_udp_server_read_cb read_cb;
   grpc_udp_server_write_cb write_cb;
   grpc_udp_server_orphan_cb orphan_cb;
+  // True if orphan_cb is trigered.
+  bool orphan_notified;
 
   struct grpc_udp_listener *next;
 };
@@ -146,6 +151,14 @@ grpc_udp_server *grpc_udp_server_create(const grpc_channel_args *args) {
   return s;
 }
 
+static void shutdown_fd(grpc_exec_ctx *exec_ctx, void *fd, grpc_error *error) {
+  grpc_fd_shutdown(exec_ctx, (grpc_fd *)fd, GRPC_ERROR_REF(error));
+}
+
+static void dummy_cb(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
+  // No-op.
+}
+
 static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
   if (s->shutdown_complete != NULL) {
     grpc_closure_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE);
@@ -195,12 +208,16 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
 
       grpc_closure_init(&sp->destroyed_closure, destroyed_port, s,
                         grpc_schedule_on_exec_ctx);
-
-      /* Call the orphan_cb to signal that the FD is about to be closed and
-       * should no longer be used. */
-      GPR_ASSERT(sp->orphan_cb);
-      sp->orphan_cb(exec_ctx, sp->emfd, sp->server->user_data);
-
+      if (!sp->orphan_notified) {
+        /* Call the orphan_cb to signal that the FD is about to be closed and
+         * should no longer be used. Because at this point, all listening ports
+         * have been shutdown already, no need to shutdown again.*/
+        grpc_closure_init(&sp->orphan_fd_closure, dummy_cb, sp->emfd,
+                          grpc_schedule_on_exec_ctx);
+        GPR_ASSERT(sp->orphan_cb);
+        sp->orphan_cb(exec_ctx, sp->emfd, &sp->orphan_fd_closure,
+                      sp->server->user_data);
+      }
       grpc_fd_orphan(exec_ctx, sp->emfd, &sp->destroyed_closure, NULL,
                      "udp_listener_shutdown");
     }
@@ -225,9 +242,11 @@ void grpc_udp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
   if (s->active_ports) {
     for (sp = s->head; sp; sp = sp->next) {
       GPR_ASSERT(sp->orphan_cb);
-      sp->orphan_cb(exec_ctx, sp->emfd, sp->server->user_data);
-      grpc_fd_shutdown(exec_ctx, sp->emfd, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
-                                               "Server destroyed"));
+      grpc_closure_init(&sp->orphan_fd_closure, shutdown_fd, sp->emfd,
+                        grpc_schedule_on_exec_ctx);
+      sp->orphan_cb(exec_ctx, sp->emfd, &sp->orphan_fd_closure,
+                    sp->server->user_data);
+      sp->orphan_notified = true;
     }
     gpr_mu_unlock(&s->mu);
   } else {
@@ -391,6 +410,7 @@ static int add_socket_to_server(grpc_udp_server *s, int fd,
     sp->read_cb = read_cb;
     sp->write_cb = write_cb;
     sp->orphan_cb = orphan_cb;
+    sp->orphan_notified = false;
     GPR_ASSERT(sp->emfd);
     gpr_mu_unlock(&s->mu);
     gpr_free(name);
diff --git a/src/core/lib/iomgr/udp_server.h b/src/core/lib/iomgr/udp_server.h
index 9df3fe4d1f..8006037644 100644
--- a/src/core/lib/iomgr/udp_server.h
+++ b/src/core/lib/iomgr/udp_server.h
@@ -55,7 +55,9 @@ typedef void (*grpc_udp_server_write_cb)(grpc_exec_ctx *exec_ctx, grpc_fd *emfd,
 
 /* Called when the grpc_fd is about to be orphaned (and the FD closed). */
 typedef void (*grpc_udp_server_orphan_cb)(grpc_exec_ctx *exec_ctx,
-                                          grpc_fd *emfd, void *user_data);
+                                          grpc_fd *emfd,
+                                          grpc_closure *shutdown_fd_callback,
+                                          void *user_data);
 
 /* Create a server, initially not bound to any ports */
 grpc_udp_server *grpc_udp_server_create(const grpc_channel_args *args);
diff --git a/src/core/lib/security/credentials/fake/fake_credentials.c b/src/core/lib/security/credentials/fake/fake_credentials.c
index 68636ba208..3fdb67fb91 100644
--- a/src/core/lib/security/credentials/fake/fake_credentials.c
+++ b/src/core/lib/security/credentials/fake/fake_credentials.c
@@ -39,11 +39,15 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/support/string.h"
 
 /* -- Fake transport security credentials. -- */
 
+#define GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS \
+  "grpc.fake_security.expected_targets"
+
 static grpc_security_status fake_transport_security_create_security_connector(
     grpc_exec_ctx *exec_ctx, grpc_channel_credentials *c,
     grpc_call_credentials *call_creds, const char *target,
@@ -88,6 +92,25 @@ grpc_server_credentials *grpc_fake_transport_security_server_credentials_create(
   return c;
 }
 
+grpc_arg grpc_fake_transport_expected_targets_arg(char *expected_targets) {
+  grpc_arg arg;
+  arg.type = GRPC_ARG_STRING;
+  arg.key = GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS;
+  arg.value.string = expected_targets;
+  return arg;
+}
+
+const char *grpc_fake_transport_get_expected_targets(
+    const grpc_channel_args *args) {
+  const grpc_arg *expected_target_arg =
+      grpc_channel_args_find(args, GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS);
+  if (expected_target_arg != NULL &&
+      expected_target_arg->type == GRPC_ARG_STRING) {
+    return expected_target_arg->value.string;
+  }
+  return NULL;
+}
+
 /* -- Metadata-only test credentials. -- */
 
 static void md_only_test_destruct(grpc_exec_ctx *exec_ctx,
diff --git a/src/core/lib/security/credentials/fake/fake_credentials.h b/src/core/lib/security/credentials/fake/fake_credentials.h
index 0fe98417c6..a28b545a67 100644
--- a/src/core/lib/security/credentials/fake/fake_credentials.h
+++ b/src/core/lib/security/credentials/fake/fake_credentials.h
@@ -38,10 +38,17 @@
 
 /* -- Fake transport security credentials. -- */
 
+/* Creates a fake transport security credentials object for testing. */
+grpc_channel_credentials *grpc_fake_transport_security_credentials_create(void);
+
+/* Creates a fake server transport security credentials object for testing. */
+grpc_server_credentials *grpc_fake_transport_security_server_credentials_create(
+    void);
+
 /* Used to verify the target names given to the fake transport security
  * connector.
  *
- * Its syntax by example:
+ * The syntax of \a expected_targets by example:
  * For LB channels:
  *     "backend_target_1,backend_target_2,...;lb_target_1,lb_target_2,..."
  * For regular channels:
@@ -50,15 +57,11 @@
  * That is to say, LB channels have a heading list of LB targets separated from
  * the list of backend targets by a semicolon. For non-LB channels, only the
  * latter is present. */
-#define GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS \
-  "grpc.test_only.fake_security.expected_target"
+grpc_arg grpc_fake_transport_expected_targets_arg(char *expected_targets);
 
-/* Creates a fake transport security credentials object for testing. */
-grpc_channel_credentials *grpc_fake_transport_security_credentials_create(void);
-
-/* Creates a fake server transport security credentials object for testing. */
-grpc_server_credentials *grpc_fake_transport_security_server_credentials_create(
-    void);
+/* Return the value associated with the expected targets channel arg or NULL */
+const char *grpc_fake_transport_get_expected_targets(
+    const grpc_channel_args *args);
 
 /* --  Metadata-only Test credentials. -- */
 
diff --git a/src/core/lib/security/transport/security_connector.c b/src/core/lib/security/transport/security_connector.c
index dbe3263f92..b15196e677 100644
--- a/src/core/lib/security/transport/security_connector.c
+++ b/src/core/lib/security/transport/security_connector.c
@@ -423,12 +423,8 @@ grpc_channel_security_connector *grpc_fake_channel_security_connector_create(
   c->base.check_call_host = fake_channel_check_call_host;
   c->base.add_handshakers = fake_channel_add_handshakers;
   c->target = gpr_strdup(target);
-  const grpc_arg *expected_target_arg =
-      grpc_channel_args_find(args, GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS);
-  if (expected_target_arg != NULL) {
-    GPR_ASSERT(expected_target_arg->type == GRPC_ARG_STRING);
-    c->expected_targets = gpr_strdup(expected_target_arg->value.string);
-  }
+  const char *expected_targets = grpc_fake_transport_get_expected_targets(args);
+  c->expected_targets = gpr_strdup(expected_targets);
   c->is_lb_channel = (grpc_lb_targets_info_find_in_args(args) != NULL);
   return &c->base;
 }
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index 97d50a91be..3e96d09798 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -1187,6 +1187,7 @@ static void finish_batch_step(grpc_exec_ctx *exec_ctx, batch_control *bctl) {
 
 static void continue_receiving_slices(grpc_exec_ctx *exec_ctx,
                                       batch_control *bctl) {
+  grpc_error *error;
   grpc_call *call = bctl->call;
   for (;;) {
     size_t remaining = call->receiving_stream->length -
@@ -1198,11 +1199,22 @@ static void continue_receiving_slices(grpc_exec_ctx *exec_ctx,
       finish_batch_step(exec_ctx, bctl);
       return;
     }
-    if (grpc_byte_stream_next(exec_ctx, call->receiving_stream,
-                              &call->receiving_slice, remaining,
+    if (grpc_byte_stream_next(exec_ctx, call->receiving_stream, remaining,
                               &call->receiving_slice_ready)) {
-      grpc_slice_buffer_add(&(*call->receiving_buffer)->data.raw.slice_buffer,
-                            call->receiving_slice);
+      error = grpc_byte_stream_pull(exec_ctx, call->receiving_stream,
+                                    &call->receiving_slice);
+      if (error == GRPC_ERROR_NONE) {
+        grpc_slice_buffer_add(&(*call->receiving_buffer)->data.raw.slice_buffer,
+                              call->receiving_slice);
+      } else {
+        grpc_byte_stream_destroy(exec_ctx, call->receiving_stream);
+        call->receiving_stream = NULL;
+        grpc_byte_buffer_destroy(*call->receiving_buffer);
+        *call->receiving_buffer = NULL;
+        call->receiving_message = 0;
+        finish_batch_step(exec_ctx, bctl);
+        return;
+      }
     } else {
       return;
     }
@@ -1213,12 +1225,24 @@ static void receiving_slice_ready(grpc_exec_ctx *exec_ctx, void *bctlp,
                                   grpc_error *error) {
   batch_control *bctl = bctlp;
   grpc_call *call = bctl->call;
+  grpc_byte_stream *bs = call->receiving_stream;
+  bool release_error = false;
 
   if (error == GRPC_ERROR_NONE) {
-    grpc_slice_buffer_add(&(*call->receiving_buffer)->data.raw.slice_buffer,
-                          call->receiving_slice);
-    continue_receiving_slices(exec_ctx, bctl);
-  } else {
+    grpc_slice slice;
+    error = grpc_byte_stream_pull(exec_ctx, bs, &slice);
+    if (error == GRPC_ERROR_NONE) {
+      grpc_slice_buffer_add(&(*call->receiving_buffer)->data.raw.slice_buffer,
+                            slice);
+      continue_receiving_slices(exec_ctx, bctl);
+    } else {
+      /* Error returned by grpc_byte_stream_pull needs to be released manually
+       */
+      release_error = true;
+    }
+  }
+
+  if (error != GRPC_ERROR_NONE) {
     if (grpc_trace_operation_failures) {
       GRPC_LOG_IF_ERROR("receiving_slice_ready", GRPC_ERROR_REF(error));
     }
@@ -1226,7 +1250,11 @@ static void receiving_slice_ready(grpc_exec_ctx *exec_ctx, void *bctlp,
     call->receiving_stream = NULL;
     grpc_byte_buffer_destroy(*call->receiving_buffer);
     *call->receiving_buffer = NULL;
+    call->receiving_message = 0;
     finish_batch_step(exec_ctx, bctl);
+    if (release_error) {
+      GRPC_ERROR_UNREF(error);
+    }
   }
 }
 
diff --git a/src/core/lib/transport/byte_stream.c b/src/core/lib/transport/byte_stream.c
index 4d4206189e..5800c70ef4 100644
--- a/src/core/lib/transport/byte_stream.c
+++ b/src/core/lib/transport/byte_stream.c
@@ -40,10 +40,15 @@
 #include "src/core/lib/slice/slice_internal.h"
 
 int grpc_byte_stream_next(grpc_exec_ctx *exec_ctx,
-                          grpc_byte_stream *byte_stream, grpc_slice *slice,
-                          size_t max_size_hint, grpc_closure *on_complete) {
-  return byte_stream->next(exec_ctx, byte_stream, slice, max_size_hint,
-                           on_complete);
+                          grpc_byte_stream *byte_stream, size_t max_size_hint,
+                          grpc_closure *on_complete) {
+  return byte_stream->next(exec_ctx, byte_stream, max_size_hint, on_complete);
+}
+
+grpc_error *grpc_byte_stream_pull(grpc_exec_ctx *exec_ctx,
+                                  grpc_byte_stream *byte_stream,
+                                  grpc_slice *slice) {
+  return byte_stream->pull(exec_ctx, byte_stream, slice);
 }
 
 void grpc_byte_stream_destroy(grpc_exec_ctx *exec_ctx,
@@ -53,16 +58,24 @@ void grpc_byte_stream_destroy(grpc_exec_ctx *exec_ctx,
 
 /* slice_buffer_stream */
 
-static int slice_buffer_stream_next(grpc_exec_ctx *exec_ctx,
-                                    grpc_byte_stream *byte_stream,
-                                    grpc_slice *slice, size_t max_size_hint,
-                                    grpc_closure *on_complete) {
+static bool slice_buffer_stream_next(grpc_exec_ctx *exec_ctx,
+                                     grpc_byte_stream *byte_stream,
+                                     size_t max_size_hint,
+                                     grpc_closure *on_complete) {
+  grpc_slice_buffer_stream *stream = (grpc_slice_buffer_stream *)byte_stream;
+  GPR_ASSERT(stream->cursor < stream->backing_buffer->count);
+  return true;
+}
+
+static grpc_error *slice_buffer_stream_pull(grpc_exec_ctx *exec_ctx,
+                                            grpc_byte_stream *byte_stream,
+                                            grpc_slice *slice) {
   grpc_slice_buffer_stream *stream = (grpc_slice_buffer_stream *)byte_stream;
   GPR_ASSERT(stream->cursor < stream->backing_buffer->count);
   *slice =
       grpc_slice_ref_internal(stream->backing_buffer->slices[stream->cursor]);
   stream->cursor++;
-  return 1;
+  return GRPC_ERROR_NONE;
 }
 
 static void slice_buffer_stream_destroy(grpc_exec_ctx *exec_ctx,
@@ -75,6 +88,7 @@ void grpc_slice_buffer_stream_init(grpc_slice_buffer_stream *stream,
   stream->base.length = (uint32_t)slice_buffer->length;
   stream->base.flags = flags;
   stream->base.next = slice_buffer_stream_next;
+  stream->base.pull = slice_buffer_stream_pull;
   stream->base.destroy = slice_buffer_stream_destroy;
   stream->backing_buffer = slice_buffer;
   stream->cursor = 0;
diff --git a/src/core/lib/transport/byte_stream.h b/src/core/lib/transport/byte_stream.h
index 1fdd5b4d77..381c65fb04 100644
--- a/src/core/lib/transport/byte_stream.h
+++ b/src/core/lib/transport/byte_stream.h
@@ -49,9 +49,10 @@ typedef struct grpc_byte_stream grpc_byte_stream;
 struct grpc_byte_stream {
   uint32_t length;
   uint32_t flags;
-  int (*next)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream,
-              grpc_slice *slice, size_t max_size_hint,
-              grpc_closure *on_complete);
+  bool (*next)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream,
+               size_t max_size_hint, grpc_closure *on_complete);
+  grpc_error *(*pull)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream,
+                      grpc_slice *slice);
   void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream);
 };
 
@@ -61,12 +62,20 @@ struct grpc_byte_stream {
  *
  * max_size_hint can be set as a hint as to the maximum number
  * of bytes that would be acceptable to read.
+ */
+int grpc_byte_stream_next(grpc_exec_ctx *exec_ctx,
+                          grpc_byte_stream *byte_stream, size_t max_size_hint,
+                          grpc_closure *on_complete);
+
+/* returns the next slice in the byte stream when it is ready (indicated by
+ * either grpc_byte_stream_next returning 1 or on_complete passed to
+ * grpc_byte_stream_next is called).
  *
  * once a slice is returned into *slice, it is owned by the caller.
  */
-int grpc_byte_stream_next(grpc_exec_ctx *exec_ctx,
-                          grpc_byte_stream *byte_stream, grpc_slice *slice,
-                          size_t max_size_hint, grpc_closure *on_complete);
+grpc_error *grpc_byte_stream_pull(grpc_exec_ctx *exec_ctx,
+                                  grpc_byte_stream *byte_stream,
+                                  grpc_slice *slice);
 
 void grpc_byte_stream_destroy(grpc_exec_ctx *exec_ctx,
                               grpc_byte_stream *byte_stream);
diff --git a/src/core/lib/transport/static_metadata.c b/src/core/lib/transport/static_metadata.c
index 599d4ad117..862cdaa8e0 100644
--- a/src/core/lib/transport/static_metadata.c
+++ b/src/core/lib/transport/static_metadata.c
@@ -97,23 +97,23 @@ static uint8_t g_bytes[] = {
     101, 105, 102, 45,  110, 111, 110, 101, 45,  109, 97,  116, 99,  104, 105,
     102, 45,  114, 97,  110, 103, 101, 105, 102, 45,  117, 110, 109, 111, 100,
     105, 102, 105, 101, 100, 45,  115, 105, 110, 99,  101, 108, 97,  115, 116,
-    45,  109, 111, 100, 105, 102, 105, 101, 100, 108, 105, 110, 107, 108, 111,
-    99,  97,  116, 105, 111, 110, 109, 97,  120, 45,  102, 111, 114, 119, 97,
-    114, 100, 115, 112, 114, 111, 120, 121, 45,  97,  117, 116, 104, 101, 110,
-    116, 105, 99,  97,  116, 101, 112, 114, 111, 120, 121, 45,  97,  117, 116,
-    104, 111, 114, 105, 122, 97,  116, 105, 111, 110, 114, 97,  110, 103, 101,
-    114, 101, 102, 101, 114, 101, 114, 114, 101, 102, 114, 101, 115, 104, 114,
-    101, 116, 114, 121, 45,  97,  102, 116, 101, 114, 115, 101, 114, 118, 101,
-    114, 115, 101, 116, 45,  99,  111, 111, 107, 105, 101, 115, 116, 114, 105,
-    99,  116, 45,  116, 114, 97,  110, 115, 112, 111, 114, 116, 45,  115, 101,
-    99,  117, 114, 105, 116, 121, 116, 114, 97,  110, 115, 102, 101, 114, 45,
-    101, 110, 99,  111, 100, 105, 110, 103, 118, 97,  114, 121, 118, 105, 97,
-    119, 119, 119, 45,  97,  117, 116, 104, 101, 110, 116, 105, 99,  97,  116,
-    101, 105, 100, 101, 110, 116, 105, 116, 121, 44,  100, 101, 102, 108, 97,
-    116, 101, 105, 100, 101, 110, 116, 105, 116, 121, 44,  103, 122, 105, 112,
-    100, 101, 102, 108, 97,  116, 101, 44,  103, 122, 105, 112, 105, 100, 101,
-    110, 116, 105, 116, 121, 44,  100, 101, 102, 108, 97,  116, 101, 44,  103,
-    122, 105, 112};
+    45,  109, 111, 100, 105, 102, 105, 101, 100, 108, 98,  45,  99,  111, 115,
+    116, 45,  98,  105, 110, 108, 105, 110, 107, 108, 111, 99,  97,  116, 105,
+    111, 110, 109, 97,  120, 45,  102, 111, 114, 119, 97,  114, 100, 115, 112,
+    114, 111, 120, 121, 45,  97,  117, 116, 104, 101, 110, 116, 105, 99,  97,
+    116, 101, 112, 114, 111, 120, 121, 45,  97,  117, 116, 104, 111, 114, 105,
+    122, 97,  116, 105, 111, 110, 114, 97,  110, 103, 101, 114, 101, 102, 101,
+    114, 101, 114, 114, 101, 102, 114, 101, 115, 104, 114, 101, 116, 114, 121,
+    45,  97,  102, 116, 101, 114, 115, 101, 114, 118, 101, 114, 115, 101, 116,
+    45,  99,  111, 111, 107, 105, 101, 115, 116, 114, 105, 99,  116, 45,  116,
+    114, 97,  110, 115, 112, 111, 114, 116, 45,  115, 101, 99,  117, 114, 105,
+    116, 121, 116, 114, 97,  110, 115, 102, 101, 114, 45,  101, 110, 99,  111,
+    100, 105, 110, 103, 118, 97,  114, 121, 118, 105, 97,  119, 119, 119, 45,
+    97,  117, 116, 104, 101, 110, 116, 105, 99,  97,  116, 101, 105, 100, 101,
+    110, 116, 105, 116, 121, 44,  100, 101, 102, 108, 97,  116, 101, 105, 100,
+    101, 110, 116, 105, 116, 121, 44,  103, 122, 105, 112, 100, 101, 102, 108,
+    97,  116, 101, 44,  103, 122, 105, 112, 105, 100, 101, 110, 116, 105, 116,
+    121, 44,  100, 101, 102, 108, 97,  116, 101, 44,  103, 122, 105, 112};
 
 static void static_ref(void *unused) {}
 static void static_unref(grpc_exec_ctx *exec_ctx, void *unused) {}
@@ -223,6 +223,7 @@ grpc_slice_refcount grpc_static_metadata_refcounts[GRPC_STATIC_MDSTR_COUNT] = {
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
+    {&grpc_static_metadata_vtable, &static_sub_refcnt},
 };
 
 const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT] = {
@@ -383,64 +384,67 @@ const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT] = {
     {.refcount = &grpc_static_metadata_refcounts[77],
      .data.refcounted = {g_bytes + 791, 13}},
     {.refcount = &grpc_static_metadata_refcounts[78],
-     .data.refcounted = {g_bytes + 804, 4}},
+     .data.refcounted = {g_bytes + 804, 11}},
     {.refcount = &grpc_static_metadata_refcounts[79],
-     .data.refcounted = {g_bytes + 808, 8}},
+     .data.refcounted = {g_bytes + 815, 4}},
     {.refcount = &grpc_static_metadata_refcounts[80],
-     .data.refcounted = {g_bytes + 816, 12}},
+     .data.refcounted = {g_bytes + 819, 8}},
     {.refcount = &grpc_static_metadata_refcounts[81],
-     .data.refcounted = {g_bytes + 828, 18}},
+     .data.refcounted = {g_bytes + 827, 12}},
     {.refcount = &grpc_static_metadata_refcounts[82],
-     .data.refcounted = {g_bytes + 846, 19}},
+     .data.refcounted = {g_bytes + 839, 18}},
     {.refcount = &grpc_static_metadata_refcounts[83],
-     .data.refcounted = {g_bytes + 865, 5}},
+     .data.refcounted = {g_bytes + 857, 19}},
     {.refcount = &grpc_static_metadata_refcounts[84],
-     .data.refcounted = {g_bytes + 870, 7}},
+     .data.refcounted = {g_bytes + 876, 5}},
     {.refcount = &grpc_static_metadata_refcounts[85],
-     .data.refcounted = {g_bytes + 877, 7}},
+     .data.refcounted = {g_bytes + 881, 7}},
     {.refcount = &grpc_static_metadata_refcounts[86],
-     .data.refcounted = {g_bytes + 884, 11}},
+     .data.refcounted = {g_bytes + 888, 7}},
     {.refcount = &grpc_static_metadata_refcounts[87],
-     .data.refcounted = {g_bytes + 895, 6}},
+     .data.refcounted = {g_bytes + 895, 11}},
     {.refcount = &grpc_static_metadata_refcounts[88],
-     .data.refcounted = {g_bytes + 901, 10}},
+     .data.refcounted = {g_bytes + 906, 6}},
     {.refcount = &grpc_static_metadata_refcounts[89],
-     .data.refcounted = {g_bytes + 911, 25}},
+     .data.refcounted = {g_bytes + 912, 10}},
     {.refcount = &grpc_static_metadata_refcounts[90],
-     .data.refcounted = {g_bytes + 936, 17}},
+     .data.refcounted = {g_bytes + 922, 25}},
     {.refcount = &grpc_static_metadata_refcounts[91],
-     .data.refcounted = {g_bytes + 953, 4}},
+     .data.refcounted = {g_bytes + 947, 17}},
     {.refcount = &grpc_static_metadata_refcounts[92],
-     .data.refcounted = {g_bytes + 957, 3}},
+     .data.refcounted = {g_bytes + 964, 4}},
     {.refcount = &grpc_static_metadata_refcounts[93],
-     .data.refcounted = {g_bytes + 960, 16}},
+     .data.refcounted = {g_bytes + 968, 3}},
     {.refcount = &grpc_static_metadata_refcounts[94],
-     .data.refcounted = {g_bytes + 976, 16}},
+     .data.refcounted = {g_bytes + 971, 16}},
     {.refcount = &grpc_static_metadata_refcounts[95],
-     .data.refcounted = {g_bytes + 992, 13}},
+     .data.refcounted = {g_bytes + 987, 16}},
     {.refcount = &grpc_static_metadata_refcounts[96],
-     .data.refcounted = {g_bytes + 1005, 12}},
+     .data.refcounted = {g_bytes + 1003, 13}},
     {.refcount = &grpc_static_metadata_refcounts[97],
-     .data.refcounted = {g_bytes + 1017, 21}},
+     .data.refcounted = {g_bytes + 1016, 12}},
+    {.refcount = &grpc_static_metadata_refcounts[98],
+     .data.refcounted = {g_bytes + 1028, 21}},
 };
 
 uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT] = {
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 4, 6, 6, 8, 8};
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 4, 6, 6, 8, 8};
 
 static const int8_t elems_r[] = {
-    10, 8,   -3,  0,  9,   21,  -76, 22,  0,   10,  -7,  0,  0,  0,  14, 0,
-    13, 12,  11,  0,  0,   0,   0,   0,   0,   0,   0,   0,  0,  0,  0,  0,
-    0,  0,   0,   0,  0,   0,   0,   0,   0,   0,   0,   0,  0,  0,  0,  0,
-    0,  -50, -51, 15, -53, -54, -55, -56, -56, -57, -58, 0,  37, 36, 35, 34,
-    33, 32,  31,  30, 29,  28,  27,  26,  25,  24,  23,  22, 21, 20, 19, 18,
-    17, 16,  15,  14, 13,  12,  11,  10,  13,  12,  11,  10, 9,  8,  7,  0};
+    10,  8,   -3,  0,   9,  21, -77, 22,  0,   10, -7,  0,   0,   0,
+    14,  0,   13,  12,  11, 0,  0,   0,   0,   0,  0,   0,   0,   0,
+    0,   0,   0,   0,   0,  0,  0,   0,   0,   0,  0,   0,   0,   0,
+    0,   0,   0,   0,   0,  0,  0,   -50, -51, 16, -53, -54, -55, -56,
+    -56, -57, -58, -59, 0,  37, 36,  35,  34,  33, 32,  31,  30,  29,
+    28,  27,  26,  25,  24, 23, 22,  21,  20,  19, 18,  17,  16,  15,
+    14,  13,  12,  11,  10, 13, 12,  11,  10,  9,  8,   7,   0};
 static uint32_t elems_phash(uint32_t i) {
   i -= 42;
-  uint32_t x = i % 96;
-  uint32_t y = i / 96;
+  uint32_t x = i % 97;
+  uint32_t y = i / 97;
   uint32_t h = x;
   if (y < GPR_ARRAY_SIZE(elems_r)) {
     uint32_t delta = (uint32_t)elems_r[y];
@@ -450,29 +454,30 @@ static uint32_t elems_phash(uint32_t i) {
 }
 
 static const uint16_t elem_keys[] = {
-    1009, 1010, 1011, 240,  241,  242,  243,  244,  138,  139,  42,   43,
-    429,  430,  431,  911,  912,  913,  712,  713,  1392, 522,  714,  1588,
-    1686, 1784, 4822, 4920, 4951, 5116, 5214, 5312, 5410, 1405, 5508, 5606,
-    5704, 5802, 5900, 5998, 6096, 6194, 6292, 6390, 6488, 6586, 6684, 6782,
-    6880, 6978, 7076, 7174, 7272, 7370, 7468, 7566, 7664, 7762, 7860, 7958,
-    8056, 8154, 8252, 8350, 8448, 1074, 1075, 1076, 1077, 8546, 8644, 8742,
-    8840, 8938, 9036, 9134, 0,    314,  0,    0,    0,    0,    0,    0,
+    1019, 1020, 1021, 242,  243,  244,  245,  246,  139,  140,  42,   43,
+    433,  434,  435,  920,  921,  922,  719,  720,  1406, 527,  721,  1604,
+    1703, 1802, 4871, 4970, 5001, 5168, 5267, 5366, 5465, 1419, 5564, 5663,
+    5762, 5861, 5960, 6059, 6158, 6257, 6356, 6455, 6554, 6653, 6752, 6851,
+    6950, 7049, 7148, 7247, 7346, 7445, 7544, 7643, 7742, 7841, 7940, 8039,
+    8138, 8237, 8336, 8435, 8534, 8633, 1085, 1086, 1087, 1088, 8732, 8831,
+    8930, 9029, 9128, 9227, 9326, 0,    317,  0,    0,    0,    0,    0,
+    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
+    0,    0,    0,    0,    0,    133,  233,  234,  0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
-    0,    0,    0,    0,    132,  231,  232,  0,    0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
-    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0};
+    0};
 static const uint8_t elem_idxs[] = {
-    73,  76,  74,  19,  20,  21,  22,  23,  15,  16,  17,  18,  11,  12,  13,
-    3,   4,   5,   0,   1,   41,  6,   2,   69,  48,  55,  24,  25,  26,  27,
+    74,  77,  75,  19,  20,  21,  22,  23,  15,  16,  17,  18,  11,  12,  13,
+    3,   4,   5,   0,   1,   41,  6,   2,   70,  48,  55,  24,  25,  26,  27,
     28,  29,  30,  7,   31,  32,  33,  34,  35,  36,  37,  38,  39,  40,  42,
     43,  44,  45,  46,  47,  49,  50,  51,  52,  53,  54,  56,  57,  58,  59,
-    60,  61,  62,  63,  64,  75,  77,  78,  79,  65,  66,  67,  68,  70,  71,
-    72,  255, 14,  255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
-    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 8,   9,   10};
+    60,  61,  62,  63,  64,  65,  76,  78,  79,  80,  66,  67,  68,  69,  71,
+    72,  73,  255, 14,  255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 8,   9,   10};
 
 grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b) {
   if (a == -1 || b == -1) return GRPC_MDNULL;
-  uint32_t k = (uint32_t)(a * 98 + b);
+  uint32_t k = (uint32_t)(a * 99 + b);
   uint32_t h = elems_phash(k);
   return h < GPR_ARRAY_SIZE(elem_keys) && elem_keys[h] == k
              ? GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[elem_idxs[h]],
@@ -706,71 +711,75 @@ grpc_mdelem_data grpc_static_mdelem_table[GRPC_STATIC_MDELEM_COUNT] = {
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[78],
-      .data.refcounted = {g_bytes + 804, 4}},
+      .data.refcounted = {g_bytes + 804, 11}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[79],
-      .data.refcounted = {g_bytes + 808, 8}},
+      .data.refcounted = {g_bytes + 815, 4}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[80],
-      .data.refcounted = {g_bytes + 816, 12}},
+      .data.refcounted = {g_bytes + 819, 8}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[81],
-      .data.refcounted = {g_bytes + 828, 18}},
+      .data.refcounted = {g_bytes + 827, 12}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[82],
-      .data.refcounted = {g_bytes + 846, 19}},
+      .data.refcounted = {g_bytes + 839, 18}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[83],
-      .data.refcounted = {g_bytes + 865, 5}},
+      .data.refcounted = {g_bytes + 857, 19}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[84],
-      .data.refcounted = {g_bytes + 870, 7}},
+      .data.refcounted = {g_bytes + 876, 5}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[85],
-      .data.refcounted = {g_bytes + 877, 7}},
+      .data.refcounted = {g_bytes + 881, 7}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[86],
-      .data.refcounted = {g_bytes + 884, 11}},
+      .data.refcounted = {g_bytes + 888, 7}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[87],
-      .data.refcounted = {g_bytes + 895, 6}},
+      .data.refcounted = {g_bytes + 895, 11}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[88],
-      .data.refcounted = {g_bytes + 901, 10}},
+      .data.refcounted = {g_bytes + 906, 6}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[89],
-      .data.refcounted = {g_bytes + 911, 25}},
+      .data.refcounted = {g_bytes + 912, 10}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[90],
-      .data.refcounted = {g_bytes + 936, 17}},
+      .data.refcounted = {g_bytes + 922, 25}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
-    {{.refcount = &grpc_static_metadata_refcounts[16],
-      .data.refcounted = {g_bytes + 200, 10}},
+    {{.refcount = &grpc_static_metadata_refcounts[91],
+      .data.refcounted = {g_bytes + 947, 17}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
-    {{.refcount = &grpc_static_metadata_refcounts[91],
-      .data.refcounted = {g_bytes + 953, 4}},
+    {{.refcount = &grpc_static_metadata_refcounts[16],
+      .data.refcounted = {g_bytes + 200, 10}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[92],
-      .data.refcounted = {g_bytes + 957, 3}},
+      .data.refcounted = {g_bytes + 964, 4}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[93],
-      .data.refcounted = {g_bytes + 960, 16}},
+      .data.refcounted = {g_bytes + 968, 3}},
+     {.refcount = &grpc_static_metadata_refcounts[20],
+      .data.refcounted = {g_bytes + 234, 0}}},
+    {{.refcount = &grpc_static_metadata_refcounts[94],
+      .data.refcounted = {g_bytes + 971, 16}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
@@ -783,24 +792,24 @@ grpc_mdelem_data grpc_static_mdelem_table[GRPC_STATIC_MDELEM_COUNT] = {
       .data.refcounted = {g_bytes + 377, 7}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
       .data.refcounted = {g_bytes + 90, 20}},
-     {.refcount = &grpc_static_metadata_refcounts[94],
-      .data.refcounted = {g_bytes + 976, 16}}},
+     {.refcount = &grpc_static_metadata_refcounts[95],
+      .data.refcounted = {g_bytes + 987, 16}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
       .data.refcounted = {g_bytes + 90, 20}},
      {.refcount = &grpc_static_metadata_refcounts[30],
       .data.refcounted = {g_bytes + 373, 4}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
       .data.refcounted = {g_bytes + 90, 20}},
-     {.refcount = &grpc_static_metadata_refcounts[95],
-      .data.refcounted = {g_bytes + 992, 13}}},
-    {{.refcount = &grpc_static_metadata_refcounts[10],
-      .data.refcounted = {g_bytes + 90, 20}},
      {.refcount = &grpc_static_metadata_refcounts[96],
-      .data.refcounted = {g_bytes + 1005, 12}}},
+      .data.refcounted = {g_bytes + 1003, 13}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
       .data.refcounted = {g_bytes + 90, 20}},
      {.refcount = &grpc_static_metadata_refcounts[97],
-      .data.refcounted = {g_bytes + 1017, 21}}},
+      .data.refcounted = {g_bytes + 1016, 12}}},
+    {{.refcount = &grpc_static_metadata_refcounts[10],
+      .data.refcounted = {g_bytes + 90, 20}},
+     {.refcount = &grpc_static_metadata_refcounts[98],
+      .data.refcounted = {g_bytes + 1028, 21}}},
 };
-const uint8_t grpc_static_accept_encoding_metadata[8] = {0,  73, 74, 75,
-                                                         76, 77, 78, 79};
+const uint8_t grpc_static_accept_encoding_metadata[8] = {0,  74, 75, 76,
+                                                         77, 78, 79, 80};
diff --git a/src/core/lib/transport/static_metadata.h b/src/core/lib/transport/static_metadata.h
index dcbe418edc..84fb316fd6 100644
--- a/src/core/lib/transport/static_metadata.h
+++ b/src/core/lib/transport/static_metadata.h
@@ -44,7 +44,7 @@
 
 #include "src/core/lib/transport/metadata.h"
 
-#define GRPC_STATIC_MDSTR_COUNT 98
+#define GRPC_STATIC_MDSTR_COUNT 99
 extern const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT];
 /* ":path" */
 #define GRPC_MDSTR_PATH (grpc_static_slice_table[0])
@@ -205,47 +205,49 @@ extern const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT];
 #define GRPC_MDSTR_IF_UNMODIFIED_SINCE (grpc_static_slice_table[76])
 /* "last-modified" */
 #define GRPC_MDSTR_LAST_MODIFIED (grpc_static_slice_table[77])
+/* "lb-cost-bin" */
+#define GRPC_MDSTR_LB_COST_BIN (grpc_static_slice_table[78])
 /* "link" */
-#define GRPC_MDSTR_LINK (grpc_static_slice_table[78])
+#define GRPC_MDSTR_LINK (grpc_static_slice_table[79])
 /* "location" */
-#define GRPC_MDSTR_LOCATION (grpc_static_slice_table[79])
+#define GRPC_MDSTR_LOCATION (grpc_static_slice_table[80])
 /* "max-forwards" */
-#define GRPC_MDSTR_MAX_FORWARDS (grpc_static_slice_table[80])
+#define GRPC_MDSTR_MAX_FORWARDS (grpc_static_slice_table[81])
 /* "proxy-authenticate" */
-#define GRPC_MDSTR_PROXY_AUTHENTICATE (grpc_static_slice_table[81])
+#define GRPC_MDSTR_PROXY_AUTHENTICATE (grpc_static_slice_table[82])
 /* "proxy-authorization" */
-#define GRPC_MDSTR_PROXY_AUTHORIZATION (grpc_static_slice_table[82])
+#define GRPC_MDSTR_PROXY_AUTHORIZATION (grpc_static_slice_table[83])
 /* "range" */
-#define GRPC_MDSTR_RANGE (grpc_static_slice_table[83])
+#define GRPC_MDSTR_RANGE (grpc_static_slice_table[84])
 /* "referer" */
-#define GRPC_MDSTR_REFERER (grpc_static_slice_table[84])
+#define GRPC_MDSTR_REFERER (grpc_static_slice_table[85])
 /* "refresh" */
-#define GRPC_MDSTR_REFRESH (grpc_static_slice_table[85])
+#define GRPC_MDSTR_REFRESH (grpc_static_slice_table[86])
 /* "retry-after" */
-#define GRPC_MDSTR_RETRY_AFTER (grpc_static_slice_table[86])
+#define GRPC_MDSTR_RETRY_AFTER (grpc_static_slice_table[87])
 /* "server" */
-#define GRPC_MDSTR_SERVER (grpc_static_slice_table[87])
+#define GRPC_MDSTR_SERVER (grpc_static_slice_table[88])
 /* "set-cookie" */
-#define GRPC_MDSTR_SET_COOKIE (grpc_static_slice_table[88])
+#define GRPC_MDSTR_SET_COOKIE (grpc_static_slice_table[89])
 /* "strict-transport-security" */
-#define GRPC_MDSTR_STRICT_TRANSPORT_SECURITY (grpc_static_slice_table[89])
+#define GRPC_MDSTR_STRICT_TRANSPORT_SECURITY (grpc_static_slice_table[90])
 /* "transfer-encoding" */
-#define GRPC_MDSTR_TRANSFER_ENCODING (grpc_static_slice_table[90])
+#define GRPC_MDSTR_TRANSFER_ENCODING (grpc_static_slice_table[91])
 /* "vary" */
-#define GRPC_MDSTR_VARY (grpc_static_slice_table[91])
+#define GRPC_MDSTR_VARY (grpc_static_slice_table[92])
 /* "via" */
-#define GRPC_MDSTR_VIA (grpc_static_slice_table[92])
+#define GRPC_MDSTR_VIA (grpc_static_slice_table[93])
 /* "www-authenticate" */
-#define GRPC_MDSTR_WWW_AUTHENTICATE (grpc_static_slice_table[93])
+#define GRPC_MDSTR_WWW_AUTHENTICATE (grpc_static_slice_table[94])
 /* "identity,deflate" */
-#define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE (grpc_static_slice_table[94])
+#define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE (grpc_static_slice_table[95])
 /* "identity,gzip" */
-#define GRPC_MDSTR_IDENTITY_COMMA_GZIP (grpc_static_slice_table[95])
+#define GRPC_MDSTR_IDENTITY_COMMA_GZIP (grpc_static_slice_table[96])
 /* "deflate,gzip" */
-#define GRPC_MDSTR_DEFLATE_COMMA_GZIP (grpc_static_slice_table[96])
+#define GRPC_MDSTR_DEFLATE_COMMA_GZIP (grpc_static_slice_table[97])
 /* "identity,deflate,gzip" */
 #define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE_COMMA_GZIP \
-  (grpc_static_slice_table[97])
+  (grpc_static_slice_table[98])
 
 extern const grpc_slice_refcount_vtable grpc_static_metadata_vtable;
 extern grpc_slice_refcount
@@ -257,7 +259,7 @@ extern grpc_slice_refcount
 #define GRPC_STATIC_METADATA_INDEX(static_slice) \
   ((int)((static_slice).refcount - grpc_static_metadata_refcounts))
 
-#define GRPC_STATIC_MDELEM_COUNT 80
+#define GRPC_STATIC_MDELEM_COUNT 81
 extern grpc_mdelem_data grpc_static_mdelem_table[GRPC_STATIC_MDELEM_COUNT];
 extern uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT];
 /* "grpc-status": "0" */
@@ -428,78 +430,81 @@ extern uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT];
 /* "lb-token": "" */
 #define GRPC_MDELEM_LB_TOKEN_EMPTY \
   (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[55], GRPC_MDELEM_STORAGE_STATIC))
+/* "lb-cost-bin": "" */
+#define GRPC_MDELEM_LB_COST_BIN_EMPTY \
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[56], GRPC_MDELEM_STORAGE_STATIC))
 /* "link": "" */
 #define GRPC_MDELEM_LINK_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[56], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[57], GRPC_MDELEM_STORAGE_STATIC))
 /* "location": "" */
 #define GRPC_MDELEM_LOCATION_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[57], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[58], GRPC_MDELEM_STORAGE_STATIC))
 /* "max-forwards": "" */
 #define GRPC_MDELEM_MAX_FORWARDS_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[58], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[59], GRPC_MDELEM_STORAGE_STATIC))
 /* "proxy-authenticate": "" */
 #define GRPC_MDELEM_PROXY_AUTHENTICATE_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[59], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[60], GRPC_MDELEM_STORAGE_STATIC))
 /* "proxy-authorization": "" */
 #define GRPC_MDELEM_PROXY_AUTHORIZATION_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[60], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[61], GRPC_MDELEM_STORAGE_STATIC))
 /* "range": "" */
 #define GRPC_MDELEM_RANGE_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[61], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[62], GRPC_MDELEM_STORAGE_STATIC))
 /* "referer": "" */
 #define GRPC_MDELEM_REFERER_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[62], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[63], GRPC_MDELEM_STORAGE_STATIC))
 /* "refresh": "" */
 #define GRPC_MDELEM_REFRESH_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[63], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[64], GRPC_MDELEM_STORAGE_STATIC))
 /* "retry-after": "" */
 #define GRPC_MDELEM_RETRY_AFTER_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[64], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[65], GRPC_MDELEM_STORAGE_STATIC))
 /* "server": "" */
 #define GRPC_MDELEM_SERVER_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[65], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[66], GRPC_MDELEM_STORAGE_STATIC))
 /* "set-cookie": "" */
 #define GRPC_MDELEM_SET_COOKIE_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[66], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[67], GRPC_MDELEM_STORAGE_STATIC))
 /* "strict-transport-security": "" */
 #define GRPC_MDELEM_STRICT_TRANSPORT_SECURITY_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[67], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[68], GRPC_MDELEM_STORAGE_STATIC))
 /* "transfer-encoding": "" */
 #define GRPC_MDELEM_TRANSFER_ENCODING_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[68], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[69], GRPC_MDELEM_STORAGE_STATIC))
 /* "user-agent": "" */
 #define GRPC_MDELEM_USER_AGENT_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[69], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[70], GRPC_MDELEM_STORAGE_STATIC))
 /* "vary": "" */
 #define GRPC_MDELEM_VARY_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[70], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[71], GRPC_MDELEM_STORAGE_STATIC))
 /* "via": "" */
 #define GRPC_MDELEM_VIA_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[71], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[72], GRPC_MDELEM_STORAGE_STATIC))
 /* "www-authenticate": "" */
 #define GRPC_MDELEM_WWW_AUTHENTICATE_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[72], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[73], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "identity" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_IDENTITY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[73], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[74], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "deflate" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_DEFLATE \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[74], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[75], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "identity,deflate" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_IDENTITY_COMMA_DEFLATE \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[75], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[76], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "gzip" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_GZIP \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[76], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[77], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "identity,gzip" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_IDENTITY_COMMA_GZIP \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[77], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[78], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "deflate,gzip" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_DEFLATE_COMMA_GZIP \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[78], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[79], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "identity,deflate,gzip" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_IDENTITY_COMMA_DEFLATE_COMMA_GZIP \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[79], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[80], GRPC_MDELEM_STORAGE_STATIC))
 
 grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b);
 typedef enum {