code: func (c *Callbacks) OnCDOTAUserMsg_Ping(fn func(*dota.CDOTAUserMsg_Ping) error) {
  	c.onCDOTAUserMsg_Ping = append(c.onCDOTAUserMsg_Ping, fn)
  }
docs: // OnCDOTAUserMsg_Ping registers a callback for EDotaUserMessages_DOTA_UM_Ping