Reset backoff when connectivity status changes (#1706)

Author: schmidt-sebastian

firebase-firestore/CHANGELOG.md

@@ -1,4 +1,7 @@
 # Unreleased
+- [fixed] Removed a delay that may have prevented Firestore from immediately
+  reestablishing a network connection if a connectivity change occurred while
+  the app was in the background.
 - [fixed] Fixed an issue that may have prevented the client from connecting
   to the backend immediately after a user signed in.
 

firebase-firestore/src/main/java/com/google/firebase/firestore/remote/RemoteStore.java

@@ -211,6 +211,9 @@ public void onClose(Status status) {
         (NetworkStatus networkStatus) -> {
           workerQueue.enqueueAndForget(
               () -> {
+                // Porting Note: Unlike iOS, `restartNetwork()` is called even when the network
+                // becomes unreachable as we don't have any other way to tear down our streams.
+
                 // If the network has been explicitly disabled, make sure we don't accidentally
                 // re-enable it.
                 if (canUseNetwork()) {
@@ -277,6 +280,8 @@ private void restartNetwork() {
     networkEnabled = false;
     disableNetworkInternal();
     onlineStateTracker.updateState(OnlineState.UNKNOWN);
+    writeStream.inhibitBackoff();
+    watchStream.inhibitBackoff();
     enableNetwork();
   }