docs: def peek(self, size=-1):
          """
          Return bytes from the stream without advancing the position.
  
          Args:
              size (int): Number of bytes to read. -1 to read the full
                  stream.
  
          Returns:
              bytes: bytes read
          """
          if not self._readable:
              raise UnsupportedOperation('read')
  
          with self._seek_lock:
              self._raw.seek(self._seek)
              return self._raw._peek(size)