code: func (c *Callbacks) OnCDOTAUserMsg_ChatEvent(fn func(*dota.CDOTAUserMsg_ChatEvent) error) {
  	c.onCDOTAUserMsg_ChatEvent = append(c.onCDOTAUserMsg_ChatEvent, fn)
  }
docs: // OnCDOTAUserMsg_ChatEvent registers a callback for EDotaUserMessages_DOTA_UM_ChatEvent