ChannelUserMessageUpdateRequest constructor
      
      ChannelUserMessageUpdateRequest({ 
    
    
- required String channelUrl,
- required int messageId,
- required UserMessageParams params,
Implementation
ChannelUserMessageUpdateRequest({
  required String channelUrl,
  required int messageId,
  required UserMessageParams params,
}) : super() {
  payload = {
    'msg_id': messageId,
    'channel_url': channelUrl,
    'message': params.message,
    'data': params.data,
    'custom_type': params.customType,
    'mention_type': params.mentionType,
    'mentioned_user_ids': params.mentionedUserIds
  };
  payload.removeWhere((key, value) => value == null);
}