code: func (refreshHandler *refreshCredentialsHandler) sendAcks() {
  	for {
  		select {
  		case ack := <-refreshHandler.ackRequest:
  			refreshHandler.ackMessage(ack)
  		case <-refreshHandler.ctx.Done():
  			return
  		}
  	}
  }
docs: // sendAcks sends ack requests to ACS