code: func (payloadHandler *payloadRequestHandler) sendAcks() {
  	for {
  		select {
  		case mid := <-payloadHandler.ackRequest:
  			payloadHandler.ackMessageId(mid)
  		case <-payloadHandler.ctx.Done():
  			return
  		}
  	}
  }
docs: // sendAcks sends ack requests to ACS