def position_changed(position)
      label_pos = Position.get(@label)
      label_pos.set(position + Parfait::BinaryCode.byte_offset)
    end
def position_changed(position)
      label_pos = Position.get(@label)
      label_pos.set(position + Parfait::BinaryCode.byte_offset)
    end
initialize with the first label of the method
 The incoming position is the first BinaryCode of the method
 We simply position the Label (instance, see initialize) as the
 first entry in the BinaryCode, at BinaryCode.byte_offset