func SendFile(dstFD *FD, src int, remain int64) (written int64, err error, handled bool) {
	defer func() {
		TestHookDidSendFile(dstFD, src, written, err, handled)
	}()
	if err := dstFD.writeLock(); err != nil {
		return 0, err, false
	}
	defer dstFD.writeUnlock()

	if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil {
		return 0, err, false
	}

	dst := dstFD.Sysfd
	for remain > 0 {
		n := maxSendfileSize

func SendFile(dstFD *FD, src int, pos, remain int64) (written int64, err error, handled bool) {
	defer func() {
		TestHookDidSendFile(dstFD, src, written, err, handled)
	}()
	if err := dstFD.writeLock(); err != nil {
		return 0, err, false
	}
	defer dstFD.writeUnlock()

	if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil {
		return 0, err, false
	}

	dst := dstFD.Sysfd
	for remain > 0 {
		n := maxSendfileSize

func SendFile(dstFD *FD, src int, pos, remain int64) (written int64, err error, handled bool) {
	defer func() {
		TestHookDidSendFile(dstFD, src, written, err, handled)
	}()
	if err := dstFD.writeLock(); err != nil {
		return 0, err, false
	}
	defer dstFD.writeUnlock()

	if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil {
		return 0, err, false
	}

	dst := dstFD.Sysfd
	for remain > 0 {
		n := maxSendfileSize

//go:build unix

package poll

import (
	"io"
	"runtime"
	"syscall"
)

// Writev wraps the writev system call.
func (fd *FD) Writev(v *[][]byte) (int64, error) {
	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()
	if err := fd.pd.prepareWrite(fd.isFile); err != nil {
		return 0, err
	}

	var iovecs []syscall.Iovec
	if fd.iovecs != nil {
		iovecs = *fd.iovecs
	}

		return 0, syscall.ESPIPE
	}
	if ft, _ := syscall.GetFileType(src); ft == syscall.FILE_TYPE_PIPE {
		return 0, syscall.ESPIPE
	}

	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()

	o := &fd.wop
	o.handle = src

	// TODO(brainman): skip calling syscall.Seek if OS allows it
	curpos, err := syscall.Seek(o.handle, 0, io.SeekCurrent)
	if err != nil {

	// locks for both file descriptors (and why this whole machinery is
	// in the internal/poll package to begin with).
	if err := dst.writeLock(); err != nil {
		return 0, err
	}
	defer dst.writeUnlock()
	if err := src.readLock(); err != nil {
		return 0, err
	}
	defer src.readUnlock()
	var n int
	for {
		n, err = unix.CopyFileRange(src.Sysfd, nil, dst.Sysfd, nil, max, 0)

		err = ErrDeadlineExceeded
	}
	return n, err
}

// Write implements io.Writer.
func (fd *FD) Write(fn func([]byte) (int, error), b []byte) (int, error) {
	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()
	fd.wmu.Lock()
	if fd.wtimedout {
		fd.wmu.Unlock()
		return 0, ErrDeadlineExceeded
	}
	fd.waio = newAsyncIO(fn, b)
	fd.wmu.Unlock()
	n, err := fd.waio.Wait()

// all of it to the socket. This behavior is similar to the Write
// step of an io.Copy in userspace.
func splicePump(sock *FD, pipefd int, inPipe int) (int, error) {
	if err := sock.writeLock(); err != nil {
		return 0, err
	}
	defer sock.writeUnlock()
	if err := sock.pd.prepareWrite(sock.isFile); err != nil {
		return 0, err
	}
	written := 0
	for inPipe > 0 {

        }
    }

    def 'invokes locking provider on writeLocks with visited modules'() {
        given:
        def identifier = newId(mid, '1.1')
        startWithoutLockState()
        addVisitedNode(identifier)

        when:
        visitor.writeLocks()

        then:

        persistentCache.withFileLock(() -> {
            // Additional locking necessary because of https://github.com/gradle/gradle/issues/3537
            lock.writeLock().lock();
            try {
                storeInsideLock(key, file);
            } finally {
                lock.writeLock().unlock();
            }
        });
    }

    private void storeInsideLock(HashCode key, File sourceFile) {