回调事件

回调类型参考:
https://pub.dev/documentation/tencent_im_plugin/latest/enums_tencent_im_listener_type_enum/TencentImListenerTypeEnum-class.html

回调监听示例：

TencentImPlugin.addListener((type, param) {
  if (type == TencentImListenerTypeEnum.EnterRoom) {
  } else if ...
});