code: func (c *Callbacks) OnCDOTAUserMsg_WillPurchaseAlert(fn func(*dota.CDOTAUserMsg_WillPurchaseAlert) error) {
  	c.onCDOTAUserMsg_WillPurchaseAlert = append(c.onCDOTAUserMsg_WillPurchaseAlert, fn)
  }
docs: // OnCDOTAUserMsg_WillPurchaseAlert registers a callback for EDotaUserMessages_DOTA_UM_WillPurchaseAlert