# File lib/sup/source.rb, line 70
  def initialize uri, initial_offset=nil, usual=true, archived=false, id=nil
    raise ArgumentError, "id must be an integer: #{id.inspect}" unless id.is_a? Fixnum if id

    @uri = uri
    @cur_offset = initial_offset
    @usual = usual
    @archived = archived
    @id = id
    @dirty = false
  end