1 files changed, 4 insertions, 0 deletions
diff --git a/javanano/src/main/java/com/google/protobuf/nano/UnknownFieldData.java b/javanano/src/main/java/com/google/protobuf/nano/UnknownFieldData.java
index a17fccf3..b1678d1b 100644
--- a/javanano/src/main/java/com/google/protobuf/nano/UnknownFieldData.java
+++ b/javanano/src/main/java/com/google/protobuf/nano/UnknownFieldData.java
@@ -42,6 +42,10 @@ import java.util.Arrays;
 final class UnknownFieldData {
 
     final int tag;
+    /**
+     * Important: this should be treated as immutable, even though it's possible
+     * to change the array values.
+     */
     final byte[] bytes;
 
     UnknownFieldData(int tag, byte[] bytes) {