if err != nil {
		return 0, err
	}
	return uintptr(fd), nil
}

func read(fd uintptr, buf []byte) (int, error) {
	return syscall.Read(int(fd), buf)
}

func closefd(fd uintptr) {
	syscall.Close(int(fd))
}

func preadn(fd uintptr, buf []byte, off int) error {
	whence := seekStart
	if off < 0 {
		whence = seekEnd
	}
	if _, err := syscall.Seek(int(fd), int64(off), whence); err != nil {

      if (civilizedFileSystem) return fileSource

      lockingSourceCount++
      return object : ForwardingSource(fileSource) {
        private var closed = false

        override fun close() {
          super.close()
          if (!closed) {
            closed = true
            synchronized(this@DiskLruCache) {
              lockingSourceCount--
              if (lockingSourceCount == 0 && zombie) {

		t.Errorf("Until did not return immediately when the stop chan was closed inside the func")
	}
}

func TestJitterUntil(t *testing.T) {
	ch := make(chan struct{})
	// if a channel is closed JitterUntil never calls function f
	// and returns immediately
	close(ch)
	JitterUntil(func() {
		t.Fatal("should not have been invoked")
	}, 0, 1.0, true, ch)

	ch = make(chan struct{})
	called := make(chan struct{})

// This will leave a goroutine running until either both channels are closed
// or the context is canceled, at which point the returned channel is closed.
func _Merge[Elem any](ctx context.Context, c1, c2 <-chan Elem) <-chan Elem {
	r := make(chan Elem)
	go func(ctx context.Context, c1, c2 <-chan Elem, r chan<- Elem) {
		defer close(r)
		for c1 != nil || c2 != nil {
			select {
			case <-ctx.Done():
				return

    }

    @Override
    public void close() {
        if (closed) {
            // Already closed.
            return;
        }
        closed = true;
        for (Loader value : loaders.values()) {
            IoActions.closeQuietly(value);
        }
    }

    private void ensureOpened() {
        if (closed) {

        thrown(IllegalStateException)
    }

    def "can close a lock multiple times"() {
        given:
        def lock = createLock(Exclusive)
        lock.close()

        expect:
        lock.close()
    }

    def "cannot read from file after lock has been closed"() {
        given:
        def lock = createLock(Exclusive)
        lock.close()

        when:
        lock.readFile({} as Supplier)

}

// Close closes the FD. The underlying file descriptor is closed by the
// destroy method when there are no remaining references.
func (fd *FD) Close() error {
	if !fd.fdmu.increfAndClose() {
		return errClosing(fd.isFile)
	}

	// Unblock any I/O.  Once it all unblocks and returns,
	// so that it cannot be referring to fd.sysfd anymore,
	// the final decref will close fd.sysfd. This should happen

    Closeables.closeQuietly(in);
    assertTrue(in.closed());
  }

  public void testCloseQuietly_readerWithEatenException() throws IOException {
    TestReader in = new TestReader(TestOption.CLOSE_THROWS);
    Closeables.closeQuietly(in);
    assertTrue(in.closed());
  }

  public void testCloseNull() throws IOException {
    Closeables.close(null, true);
    Closeables.close(null, false);
  }

	}()

	if ln, err := Listen("tcp", ""); err == nil {
		ln.Close()
	}
	if ln, err := ListenPacket("udp", ""); err == nil {
		ln.Close()
	}
	if ln, err := ListenTCP("tcp", nil); err == nil {
		ln.Close()
	}
	if ln, err := ListenUDP("udp", nil); err == nil {
		ln.Close()
	}
	if ln, err := ListenIP("ip:icmp", nil); err == nil {
		ln.Close()
	}
}

var ipv4MulticastListenerTests = []struct {

			skipOrFatalFn()
			continue
		}

		c1, err := ListenPacket(tt.net, tt.addr1)
		if err != nil {
			t.Fatal(err)
		}
		defer closer(c1, tt.net, tt.addr1, tt.addr2)
		c1.LocalAddr()

		c2, err := ListenPacket(tt.net, tt.addr2)
		if err != nil {
			t.Fatal(err)
		}
		defer closer(c2, tt.net, tt.addr1, tt.addr2)
		c2.LocalAddr()
		rb2 := make([]byte, 128)

		if _, err := c1.WriteTo(wb, c2.LocalAddr()); err != nil {