class BinData::DelayedIO

def read_now!

The reading is delayed until this method is called.
DelayedIO objects aren't read when #read is called. 
def read_now!
  return unless include_obj?
  raise IOError, "read from where?" unless @read_io
  @read_io.seekbytes(abs_offset - @read_io.offset)
  start_read do
    @type.do_read(@read_io)
  end
end