`io.UnsupportedOperation: seek` when using `torchaudio.io.StreamWriter` with a File-like object

🐛 Describe the bug

In the tutorial for StreamWriter, it is clearly stated that StreamWriter works with File-like object that implements io.RawIOBase.write. However, when I used StreamWriter with the Google Cloud Storage BlobWriter object that implements write but not seek, an error is thrown on calling StreamWriter.close():

from google.cloud.storage import Blob
from torch.io import StreamWriter

blob = Blob(name=..., bucket=...)

with blob.open("wb") as f:
    writer = StreamWriter(dst=f)
    with writer.open():
        ...

self = <torio.io._streaming_media_encoder.StreamingMediaEncoder object at 0x110096190>

    def close(self):
        """Close the output
    
        :py:class:`StreamingMediaEncoder` is also a context manager and therefore supports the
        ``with`` statement.
        It is recommended to use context manager, as the file is closed automatically
        when exiting from ``with`` clause.
    
        See :py:meth:`StreamingMediaEncoder.open` for more detail.
        """
        if self._is_open:
>           self._s.close()
E           io.UnsupportedOperation: seek

.venv/lib/python3.11/site-packages/torio/io/_streaming_media_encoder.py:451: UnsupportedOperation

Clearly seek is called in close(), which causes this error. For now, can I get around this issue by not calling close on the writer object but do call close the blob object?

Versions

google-cloud-storage 3.1.0
torchaudio 2.6.0

Start with torio/io/_streaming_media_encoder.py at the close path shown in the traceback, then compare its behavior with the StreamWriter file-like objects tutorial and reproduce it using Google Cloud Storage BlobWriter. Determine how a write-only object is handled on close and document or correct the behavior, including the safe workaround requested by the report.