startCallback method
Starts contact and group, chatroom callback.
Call this method when you UI is ready, then will receive ChatRoomEventHandler, ContactEventHandler, ChatGroupEventHandler event.
Implementation
Future<void> startCallback() async {
Map result = await ClientChannel.invokeMethod(ChatMethodKeys.startCallback);
try {
ChatError.hasErrorFromResult(result);
} on ChatError catch (e) {
throw e;
}
}