docs: def update(self, incoming_stream, seek=0, size=None, chunk_size=None,
                 progress_callback=None):
          """Update a file in the file system."""
          fp = self.open(mode='r+b')
          try:
              fp.seek(seek)
              bytes_written, checksum = self._write_stream(
                  incoming_stream, fp, chunk_size=chunk_size,
                  size=size, progress_callback=progress_callback)
          finally:
              fp.close()
  
          return bytes_written, checksum