code: ConversationComparison compare(boolean successful, List<Conversation> remote, List<ChatConversationBase> local) {
          return new ConversationComparison(successful, makeMapFromDownloadedConversations(remote), makeMapFromSavedConversations(local));
      }
docs: Compares remote and local conversation lists.
  
  @param successful True if the service call was successful.
  @param remote     Conversation list obtained from the server.
  @param local      Conversation list obtained from local store.
  @return Comparison object.