code: func (t *MockTransport) DialTimeout(addr string, timeout time.Duration) (net.Conn, error) {
  	dest, ok := t.net.transports[addr]
  	if !ok {
  		return nil, fmt.Errorf("No route to %q", addr)
  	}
  
  	p1, p2 := net.Pipe()
  	dest.streamCh <- p1
  	return p2, nil
  }
docs: // See Transport.