{seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},
		{seek: io.SeekStart, n: 5, want: "01234"},
		{seek: io.SeekCurrent, n: 5, want: "56789"},
		{seek: io.SeekEnd, off: -1, n: 1, wantpos: 9, want: "9"},
	}

	for i, tt := range tests {
		pos, err := r.Seek(tt.off, tt.seek)
		if err == nil && tt.seekerr != "" {
			t.Errorf("%d. want seek error %q", i, tt.seekerr)
			continue
		}

	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:

	return nil
}

// Seek implements the [io.Seeker] interface.
func (r *Reader) Seek(offset int64, whence int) (int64, error) {
	r.prevRune = -1
	var abs int64
	switch whence {
	case io.SeekStart:
		abs = offset
	case io.SeekCurrent:
		abs = r.i + offset
	case io.SeekEnd:
		abs = int64(len(r.s)) + offset
	default:
		return 0, errors.New("bytes.Reader.Seek: invalid whence")
	}
	if abs < 0 {

        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.

  CHECK(v2_reader_ != nullptr);
  CHECK(v2_reader_->status().ok());

  // First pass: filters out the entries of the slices.
  std::unordered_set<string> filtered_keys;
  BundleEntryProto entry;
  v2_reader_->Seek(kHeaderEntryKey);
  for (v2_reader_->Next(); v2_reader_->Valid(); v2_reader_->Next()) {
    CHECK(entry.ParseFromString(v2_reader_->value()))
        << entry.InitializationErrorString();

		// 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

      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()
  }

United States and other governments.  
It is your responsibility to ensure that your use and/or transfer does not
violate applicable laws. 

For more information, please see http://www.bis.doc.gov

* `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(data)`: Escreve `data` (`str` ou `bytes`) no arquivo.
* `read(size)`: Lê `size` (`int`) bytes/caracteres do arquivo.
* `seek(offset)`: Vai para o byte na posição `offset` (`int`) no arquivo.
    * Por exemplo, `await myfile.seek(0)` irá para o início do arquivo.
    * Isso é especialmente útil se você executar `await myfile.read()` uma vez e precisar ler o conteúdo novamente.
* `close()`: Fecha o arquivo.