addReceiveChatRoomMessageListener method Null safety

dynamic addReceiveChatRoomMessageListener(
  1. String? listenerID,
  2. JMReceiveChatRoomMessageListener callback
)

Implementation

addReceiveChatRoomMessageListener(
    String? listenerID, JMReceiveChatRoomMessageListener callback) {
  if (listenerID == null) {
    print(flutterLog + "'listenerID' is can not be null.");
    return;
  }
  _eventHanders.receiveChatRoomMessageMap[listenerID] = callback;
}