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 {
		return 0, err
	}

	if n <= 0 { // We don't know the size of the file so infer it.
		// Find the number of bytes offset from curpos until the end of the file.
		n, err = syscall.Seek(o.handle, -curpos, io.SeekEnd)
		if err != nil {
			return
		}

	// a bit brittle but cannot be addressed without a large change of the
	// algorithm in the os.(*File).readdir method.
	return n - len(b), nil
}

// Seek wraps syscall.Seek.
func (fd *FD) Seek(offset int64, whence int) (int64, error) {
	if err := fd.incref(); err != nil {
		return 0, err
	}
	defer fd.decref()
	// syscall.Filetype is a uint8 but we store it as a uint32 in SysFile in

        To be awaitable, compatible with async, this is run in threadpool.
        """
        return await super().read(size)

    async def seek(
        self,
        offset: Annotated[
            int,
            Doc(
                """
                The position in bytes to seek to in the file.
                """
            ),
        ],
    ) -> None:
        """
        Move to a position in the file.

	case AIAMAG:
		return nil, fmt.Errorf("small AIX archive not supported")
	default:
		return nil, fmt.Errorf("unrecognised archive magic: 0x%x", magic)
	}

	var fhdr bigarFileHeader
	if _, err := sr.Seek(0, io.SeekStart); err != nil {
		return nil, err
	}
	if err := binary.Read(sr, binary.BigEndian, &fhdr); err != nil {
		return nil, err
	}

	off, err := parseDecimalBytes(fhdr.Flfstmoff[:])
	if err != nil {

	// of the file -- if you pass it offset 0, it starts from
	// offset 0. There's no way to tell it "start from current
	// position", so we have to manage that explicitly.
	pos, err := f.Seek(0, io.SeekCurrent)
	if err != nil {
		return 0, err, false
	}

	sc, err := f.SyscallConn()
	if err != nil {
		return 0, nil, false
	}

	var werr error
	err = sc.Read(func(fd uintptr) bool {

    options:
        members:
            - file
            - filename
            - size
            - headers
            - content_type
            - read
            - write
            - seek

    options:
        members:
            - file
            - filename
            - size
            - headers
            - content_type
            - read
            - write
            - seek

    public LockInfo readLockInfo(RandomAccessFile lockFileAccess) throws IOException {
        if (lockFileAccess.length() <= infoRegionPos) {
            return new LockInfo();
        } else {
            lockFileAccess.seek(infoRegionPos);

            DataInputStream inputStream = new DataInputStream(new BufferedInputStream(new RandomAccessFileInputStream(lockFileAccess)));
            byte protocolVersion = inputStream.readByte();

}

func (cfw *CoverageDataWriter) patchSegmentHeader(ws *slicewriter.WriteSeeker) error {
	// record position
	off, err := ws.Seek(0, io.SeekCurrent)
	if err != nil {
		return fmt.Errorf("error seeking in patchSegmentHeader: %v", err)
	}
	// seek back to start so that we can update the segment header
	if _, err := ws.Seek(0, io.SeekStart); err != nil {
		return fmt.Errorf("error seeking in patchSegmentHeader: %v", err)
	}
	if cfw.debug {

      sinkBuffer.write(maskKey)

      if (length > 0) {
        val payloadStart = sinkBuffer.size
        sinkBuffer.write(payload)

        sinkBuffer.readAndWriteUnsafe(maskCursor!!)
        maskCursor.seek(payloadStart)
        toggleMask(maskCursor, maskKey)
        maskCursor.close()
      }
    } else {
      sinkBuffer.writeByte(b1)
      sinkBuffer.write(payload)
    }

    sink.flush()
  }