c.Control(func(fdPtr uintptr) {
			// got socket file descriptor to set parameters.
			fd := int(fdPtr)

			_ = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_REUSEADDR, 1)

			_ = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_REUSEPORT, 1)

			// Enable custom socket send/recv buffers.
			if opts.SendBufSize > 0 {
				_ = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_SNDBUF, opts.SendBufSize)
			}

			if opts.RecvBufSize > 0 {

  @Test
  fun testFileDescriptor() {
    assertOnFileDescriptor { fd ->
      val requestBody = fd.toRequestBody()

      assertThat(requestBody.contentLength()).isEqualTo(-1L)
      assertThat(requestBody.isOneShot()).isEqualTo(true)
    }
  }

  @Test
  fun testFileDescriptorRead() {
    assertOnFileDescriptor(content = "Hello") { fd ->
      val requestBody = fd.toRequestBody()

      val buffer = Buffer()

	}
	return nil
}

// openFileWithFD return 'fd' based file descriptor
func openFileWithFD(name string, flag int, perm os.FileMode) (fd int, err error) {
	switch flag & writeMode {
	case writeMode:
		defer updateOSMetrics(osMetricOpenFileWFd, name)(err)
	default:
		defer updateOSMetrics(osMetricOpenFileRFd, name)(err)
	}
	var e error
	fd, e = syscall.Open(name, flag|syscall.O_CLOEXEC, uint32(perm))
	if e != nil {

	}
}

// NewLexer returns a lexer for the named file and the given link context.
func NewLexer(name string) TokenReader {
	input := NewInput(name)
	fd, err := os.Open(name)
	if err != nil {
		log.Fatalf("%s\n", err)
	}
	input.Push(NewTokenizer(name, fd, fd))
	return input
}

// The other files in this directory each contain an implementation of TokenReader.

	return directio.OpenFile(filePath, flag, perm)
}

// DisableDirectIO - disables directio mode.
func DisableDirectIO(f *os.File) error {
	fd := f.Fd()
	flag, err := unix.FcntlInt(fd, unix.F_GETFL, 0)
	if err != nil {
		return err
	}
	flag &= ^(syscall.O_DIRECT)
	_, err = unix.FcntlInt(fd, unix.F_SETFL, flag)
	return err
}

// AlignedBlock - pass through to directio implementation.
func AlignedBlock(blockSize int) []byte {

	fd, err := syscall.CreateFile(pathp, access, shareflag, nil, createflag, accessAttr, 0)
	if err != nil {
		return nil, err
	}

	return os.NewFile(uintptr(fd), path), nil
}

func lockFile(fd syscall.Handle, flags uint32) error {
	// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365203(v=vs.85).aspx
	if fd == syscall.InvalidHandle {
		return nil
	}

	return directio.OpenFile(filePath, flag, perm)
}

// DisableDirectIO - disables directio mode.
func DisableDirectIO(f *os.File) error {
	fd := f.Fd()
	_, err := unix.FcntlInt(fd, unix.F_NOCACHE, 0)
	return err
}

// AlignedBlock - pass through to directio implementation.
func AlignedBlock(blockSize int) []byte {
	return directio.AlignedBlock(blockSize)

    /**
     * Tests whether this file descriptor is open and valid.
     *
     * @return whether the FD is open and valid
     */
    boolean isOpen();

    /**
     * Tests whether this file descriptor was previously open but has become invalid.
     *
     * @return whether the FD was previously open but became invalid
     */
    boolean isStale();

    /**

// Package lock - implements filesystem locking wrappers around an
// open file descriptor.
package lock

import (
	"errors"
	"os"
	"sync"
)

// ErrAlreadyLocked is returned if the underlying fd is already locked.
var ErrAlreadyLocked = errors.New("file already locked")

// RLockedFile represents a read locked file, implements a special
// closer which only closes the associated *os.File when the ref count.

     */
    @Override
    public int available() throws IOException {
        try (SmbFileHandleImpl fd = this.handle.ensureOpen(); SmbTreeHandleImpl th = fd.getTree()) {
            if (th.isSMB2()) {
                final Smb2IoctlRequest req = new Smb2IoctlRequest(th.getConfig(), Smb2IoctlRequest.FSCTL_PIPE_PEEK, fd.getFileId());
                req.setMaxOutputResponse(16);