code: func (n *MockNetwork) NewTransport() *MockTransport {
  	n.port += 1
  	addr := fmt.Sprintf("127.0.0.1:%d", n.port)
  	transport := &MockTransport{
  		net:      n,
  		addr:     &MockAddress{addr},
  		packetCh: make(chan *Packet),
  		streamCh: make(chan net.Conn),
  	}
  
  	if n.transports == nil {
  		n.transports = make(map[string]*MockTransport)
  	}
  	n.transports[addr] = transport
  	return transport
  }
docs: // NewTransport returns a new MockTransport with a unique address, wired up to
  // talk to the other transports in the MockNetwork.