t.Error(err)
				return
			}
		}
		ls := newLocalServer(t, "tcp")
		defer ls.teardown()
		if err := ls.buildup(handler); err != nil {
			t.Fatal(err)
		}

		c, err := Dial(ls.Listener.Addr().Network(), ls.Listener.Addr().String())
		if err != nil {
			t.Fatal(err)
		}
		defer c.Close()

		cc, err := c.(*TCPConn).SyscallConn()
		if err != nil {
			t.Fatal(err)
		}

				return
			}

			if _, err := io.Copy(conn, f); err != nil {
				b.Errorf("failed to copy: %v", err)
				return
			}
		}
	}(ln, fileName)

	conn, err := Dial("tcp", ln.Addr().String())
	if err != nil {
		b.Fatalf("failed to dial: %v", err)
	}
	defer conn.Close()

	n, err := io.CopyN(io.Discard, conn, int64(dataSize))
	if err != nil {
		b.Fatalf("failed to copy: %v", err)
	}

	t.Run("default resolver", f)
	t.Run("forced go resolver", func(t *testing.T) {
		// On plan9 the forceGoDNS might not force the go resolver, currently
		// it is only forced when the Resolver.Dial field is populated.
		// See conf.go mustUseGoResolver.
		defer forceGoDNS()()
		f(t)
	})
	t.Run("forced cgo resolver", func(t *testing.T) {
		defer forceCgoDNS()()
		f(t)
	})
}

		w.Write([]byte("hello"))
	}))
	dial := func() net.Conn {
		c, err := net.Dial("tcp", ts.Listener.Addr().String())
		if err != nil {
			t.Fatal(err)
		}
		return c
	}

	// Keep one connection in StateNew (connected, but not sending anything)
	cnew := dial()
	defer cnew.Close()

	// Keep one connection in StateIdle (idle after a request)
	cidle := dial()
	defer cidle.Close()

					RCode:    dnsmessage.RCodeSuccess,
				},
				Questions: q.Questions,
			}
			if n == "udp" {
				r.Header.Truncated = true
			}
			return r, nil
		},
	}
	r := Resolver{PreferGo: true, Dial: fake.DialContext}
	for _, tt := range dnsTransportFallbackTests {
		ctx, cancel := context.WithCancel(context.Background())
		defer cancel()
		_, h, err := r.exchange(ctx, tt.server, tt.question, time.Second, useUDPOrTCP, false)

		}
		c.SetKeepAliveConfig(keepAliveCfg)
		if keepAliveHook != nil {
			keepAliveHook(keepAliveCfg)
		}
	}
	return c
}

// DialTCP acts like [Dial] for TCP networks.
//
// The network must be a TCP network name; see func Dial for details.
//
// If laddr is nil, a local address is automatically chosen.
// If the IP field of raddr is nil or an unspecified IP address, the
// local system is assumed.

				w.Header().Set("X-Status", "ok")
			})).ts

			var writeNumAtomic int32
			c := ts.Client()
			c.Transport.(*Transport).Dial = func(network, addr string) (net.Conn, error) {
				logf("Dial")
				c, err := net.Dial(network, ts.Listener.Addr().String())
				if err != nil {
					logf("Dial error: %v", err)
					return nil, err
				}
				return &writerFuncConn{
					Conn: c,

	go func() {
		c, err := ln.Accept()
		if err != nil {
			return
		}
		time.Sleep(time.Millisecond)
		var buf [1]byte
		c.Write(buf[:])
		c.Close()
	}()
	c, err := net.Dial("tcp", ln.Addr().String())
	if err != nil {
		log.Fatalf("dial failed: %v", err)
	}
	var tmp [1]byte
	c.Read(tmp[:])
	c.Close()

	trace.Stop()
}

// blockingSyscall blocks the current goroutine for duration d in a syscall and

			c, err := ln.Accept()
			if err != nil {
				return
			}
			time.Sleep(time.Millisecond)
			var buf [1]byte
			c.Write(buf[:])
			c.Close()
		}()
		c, err := net.Dial("tcp", ln.Addr().String())
		if err != nil {
			log.Fatalf("dial failed: %v", err)
			return
		}
		var tmp [1]byte
		c.Read(tmp[:])
		c.Close()

		go func() {
			runtime.Gosched()
			select {}
		}()

	done1 <- true
	<-done2
	select {
	case c1 <- 0:
	case c2 <- 0:
	}
	mu.Unlock()
	wg.Done()
	cv.Signal()
	c, err := net.Dial("tcp", ln.Addr().String())
	if err != nil {
		log.Fatalf("failed to dial: %v", err)
	}
	c.Close()
	var data [1]byte
	wp.Write(data[:])
	<-pipeReadDone

	oldGoMaxProcs := runtime.GOMAXPROCS(0)
	runtime.GOMAXPROCS(oldGoMaxProcs + 1)