Create an enum for sender errors

Will replace usages of bools, and will now currently only be used
for indicating that messages were sent too fast

After we merge this commit we will replace this enum with a general
Status class for all of aos, similar to absl::Status.

Change-Id: I4b5b2e7685744b3c6826a241cd3c84190eaa96ee
Signed-off-by: milind-u <milind.upadhyay@gmail.com>
diff --git a/aos/network/message_bridge_server.fbs b/aos/network/message_bridge_server.fbs
index cdf970c..128f1f3 100644
--- a/aos/network/message_bridge_server.fbs
+++ b/aos/network/message_bridge_server.fbs
@@ -40,6 +40,9 @@
 // Statistics for all connections to all the clients.
 table ServerStatistics {
   connections:[ServerConnection] (id: 0);
+
+  // Count of timestamp send failures
+  timestamp_send_failures:uint64 (id: 1);
 }
 
 root_type ServerStatistics;