# File lib/sup/thread.rb, line 219
  def dump_recursive f=$stdout, indent=0, root=true, parent=nil
    raise "inconsistency" unless parent.nil? || parent.children.include?(self)
    unless root
      f.print " " * indent
      f.print "+->"
    end
    line = "[#{thread.nil? ? ' ' : '*'}] " + #"[#{useful? ? 'U' : ' '}] " +
      if @message
        message.subj ##{@message.refs.inspect} / #{@message.replytos.inspect}"
      else
        "<no message>"
      end

    f.puts "#{id} #{line}"#[0 .. (105 - indent)]
    indent += 3
    @children.each { |c| c.dump_recursive f, indent, false, self }
  end