public override void MessageReceived(AgoraRtmChannel channel, AgoraRtmMessage message, AgoraRtmMember member)
 {
     InvokeOnMainThread(() => OnMessageReceived(member.UserId, message));
 }
 public override void MemberLeft(AgoraRtmChannel channel, AgoraRtmMember member)
 {
     InvokeOnMainThread(() => ShowAlert(member.UserId, "Left"));
 }