AckClientTransaction constructor
      
      AckClientTransaction(
    
    
- PitelUA ua,
- Transport transport,
- OutgoingRequest request,
- EventManager eventHandlers,
Implementation
AckClientTransaction(PitelUA ua, Transport transport, OutgoingRequest request,
    EventManager eventHandlers) {
  id = 'z9hG4bK${Math.floor(Math.random() * 10000000)}';
  this.transport = transport;
  this.request = request;
  _eventHandlers = eventHandlers;
  String via = 'SIP/2.0/${transport.via_transport}';
  via += ' ${ua.configuration!.via_host};branch=$id';
  request.setHeader('via', via);
}