Replace `QueryListenOptions` with simple booleans (#1106)

* Replace `QueryListenOptions` with simple booleans

Instead of calling

  addSnapshotListener(
      options:QueryListenOptions.includeQueryMetadataChanges()
                                .includeDocumentMetadataChanges())

call

  addSnapshotListener(includeMetadataChanges:true)

Also change `QuerySnapshot.documentChanges()` into a method which
optionally takes `includeMetadataChanges:true`. By default even when
listening to a query with `inlcudeMetadataChanges:true` metadata-only
document changes are suppressed because they're confusing.

* Revert QuerySnapshot.documentChanges back to a property

Add usage.

1 files changed, 20 insertions, 1 deletions

diff --git a/Firestore/Example/SwiftBuildTest/main.swift b/Firestore/Example/SwiftBuildTest/main.swift
index ad6c0f6..8de5ed4 100644
--- a/Firestore/Example/SwiftBuildTest/main.swift
+++ b/Firestore/Example/SwiftBuildTest/main.swift
@@ -321,6 +321,26 @@ func listenToQueryDiffs(onQuery query: Query) {
   listener.remove()
 }
 
+func listenToQueryDiffsWithMetadata(onQuery query: Query) {
+  let listener = query.addSnapshotListener(includeMetadataChanges: true) { snap, error in
+    if let snap = snap {
+      for change in snap.documentChanges(includeMetadataChanges: true) {
+        switch change.type {
+        case .added:
+          print("New document: \(change.document.data())")
+        case .modified:
+          print("Modified document: \(change.document.data())")
+        case .removed:
+          print("Removed document: \(change.document.data())")
+        }
+      }
+    }
+  }
+
+  // Unsubscribe
+  listener.remove()
+}
+
 func transactions() {
   let db = Firestore.firestore()
 
@@ -361,7 +381,6 @@ func types() {
   let _: GeoPoint
   let _: Timestamp
   let _: ListenerRegistration
-  let _: QueryListenOptions
   let _: Query
   let _: QuerySnapshot
   let _: SnapshotMetadata