code: func (c *Callbacks) OnCSVCMsg_FlattenedSerializer(fn func(*dota.CSVCMsg_FlattenedSerializer) error) {
  	c.onCSVCMsg_FlattenedSerializer = append(c.onCSVCMsg_FlattenedSerializer, fn)
  }
docs: // OnCSVCMsg_FlattenedSerializer registers a callback for SVC_Messages_svc_FlattenedSerializer