code: func (c *Callbacks) OnCDOTAUserMsg_HPManaAlert(fn func(*dota.CDOTAUserMsg_HPManaAlert) error) {
  	c.onCDOTAUserMsg_HPManaAlert = append(c.onCDOTAUserMsg_HPManaAlert, fn)
  }
docs: // OnCDOTAUserMsg_HPManaAlert registers a callback for EDotaUserMessages_DOTA_UM_HPManaAlert