# File lib/taps/data_stream.rb, line 304
  def fetch_buffered(chunksize)
    load_buffer(chunksize) if self.buffer.size < chunksize
    rows = buffer.slice(0, chunksize)
    state[:last_fetched] = if rows.size > 0
      rows.last[ primary_key ]
    else
      nil
    end
    rows
  end