def advance(self, blocksize):
        """Add blocksize seconds more to the buffer, push blocksize seconds
        from the beginning.

        Parameters
        ----------
        blocksize: int
            The number of seconds to attempt to read from the channel
        """
        ts = self._read_frame(blocksize)

        self.raw_buffer.roll(-len(ts))
        self.raw_buffer[-len(ts):] = ts[:]
        self.read_pos += blocksize
        self.raw_buffer.start_time += blocksize
        return ts