code: func (c *Callbacks) OnCDOTAUserMsg_ItemSold(fn func(*dota.CDOTAUserMsg_ItemSold) error) {
  	c.onCDOTAUserMsg_ItemSold = append(c.onCDOTAUserMsg_ItemSold, fn)
  }
docs: // OnCDOTAUserMsg_ItemSold registers a callback for EDotaUserMessages_DOTA_UM_ItemSold