/// <summary>
/// 方法说明：通过SDK发送自定义消息接口：[支持4000-9999的自定义消息，仅仅是传输][完成自定义消息（MsCustomEntity）中的content内容]
/// 完成时间：2017-05-16
/// </summary>
/// <param name="entity">发送消息实体</param>
/// <param name="custommsgType">自定义消息类型[4000-9999]</param>
/// <param name="customTopic">自定义主题</param>
/// <param name="errorMsg">提示信息</param>
/// <returns>是否成功发送消息</returns>
public bool SdkPublishCustomMsg(MsSdkCustomEntity entity, int custommsgType, string customTopic,
ref string errorMsg)
{
var jsonStr = MsgConverter.GetJsonByCustomMsg(entity, custommsgType.ToString(), ref errorMsg);
return(!string.IsNullOrEmpty(jsonStr) && Publish(customTopic, jsonStr, false, ref errorMsg));
}