try ( SmbRandomAccessFile raf = new SmbRandomAccessFile(f, "r") ) {
                    raf.seek(10);
                    Assert.assertEquals(-1, raf.read());
                }

                byte[] buf = new byte[4];
                try ( SmbRandomAccessFile raf = new SmbRandomAccessFile(f, "r") ) {
                    raf.seek(6);
                    Assert.assertEquals(2, raf.read(buf));

		// io.Seeker, but calling Seek always returns an error and performs
		// no action. Thus, we try an innocent seek to the current position
		// to see if Seek is really supported.
		pos1, err := sr.Seek(0, io.SeekCurrent)
		if pos1 >= 0 && err == nil {
			// Seek seems supported, so perform the real Seek.
			pos2, err := sr.Seek(n-1, io.SeekCurrent)
			if pos2 < 0 || err != nil {
				return err

	return &ObjectReadSeekCloser{
		segmentReader: segmentReader,
		size:          actualSize,
		offset:        0,
		reader:        nil,
	}
}

// Seek call to implement io.Seeker
func (rsc *ObjectReadSeekCloser) Seek(offset int64, whence int) (int64, error) {
	// fmt.Printf("actual: %v offset: %v (%v) whence: %v\n", rsc.size, offset, rsc.offset, whence)
	switch whence {
	case io.SeekStart:

    if (frameLength > 0L) {
      source.readFully(controlFrameBuffer, frameLength)

      if (!isClient) {
        controlFrameBuffer.readAndWriteUnsafe(maskCursor!!)
        maskCursor.seek(0)
        toggleMask(maskCursor, maskKey!!)
        maskCursor.close()
      }
    }

    when (opcode) {
      OPCODE_CONTROL_PING -> {

* `write(data)`: Writes `data` (`str` or `bytes`) to the file.
* `read(size)`: Reads `size` (`int`) bytes/characters of the file.
* `seek(offset)`: Goes to the byte position `offset` (`int`) in the file.
    * E.g., `await myfile.seek(0)` would go to the start of the file.
    * This is especially useful if you run `await myfile.read()` once and then need to read the contents again.
* `close()`: Closes the file.

* `write(daten)`: Schreibt `daten` (`str` oder `bytes`) in die Datei.
* `read(anzahl)`: Liest `anzahl` (`int`) bytes/Zeichen aus der Datei.
* `seek(versatz)`: Geht zur Position `versatz` (`int`) in der Datei.
    * Z. B. würde `await myfile.seek(0)` zum Anfang der Datei gehen.
    * Das ist besonders dann nützlich, wenn Sie `await myfile.read()` einmal ausführen und dann diese Inhalte erneut auslesen müssen.

* `write(data)`: escreve dados (`data`) em `str` ou `bytes` no arquivo.
* `read(size)`: Lê um número de bytes/caracteres de acordo com a quantidade `size` (`int`).
* `seek(offset)`: Navega para o byte na posição `offset` (`int`) do arquivo.
    * E.g., `await myfile.seek(0)` navegaria para o ínicio do arquivo.
    * Isso é especialmente útil se você executar `await myfile.read()` uma vez e depois precisar ler os conteúdos do arquivo de novo.

	default:
		return n, nil
	}
}

func (sw *sparseFileWriter) ReadFrom(r io.Reader) (n int64, err error) {
	rs, ok := r.(io.ReadSeeker)
	if ok {
		if _, err := rs.Seek(0, io.SeekCurrent); err != nil {
			ok = false // Not all io.Seeker can really seek
		}
	}
	if !ok {
		return io.Copy(struct{ io.Writer }{sw}, r)
	}

	var readLastByte bool
	pos0 := sw.pos

	}
	f.pos += int64(len(b))
	return len(b), nil
}

func (f *testFile) Seek(pos int64, whence int) (int64, error) {
	if pos == 0 && whence == io.SeekCurrent {
		return f.pos, nil
	}
	if len(f.ops) == 0 {
		return 0, errors.New("unexpected Seek operation")
	}
	s, ok := f.ops[0].(int64)
	if !ok {
		return 0, errors.New("unexpected Seek operation")
	}

	if s != pos || whence != io.SeekCurrent {

* `write(data)`: Записать данные `data` (`str` или `bytes`) в файл.
* `read(size)`: Прочитать количество `size` (`int`) байт/символов из файла.
* `seek(offset)`: Перейти к байту на позиции `offset` (`int`) в файле.
    * Наример, `await myfile.seek(0)` перейдет к началу файла.
    * Это особенно удобно, если вы один раз выполнили команду `await myfile.read()`, а затем вам нужно прочитать содержимое файла еще раз.