# File lib/slave-1.2.1.rb, line 250
      def on_cut &b
        at_exit{ begin; b.call; ensure; b = nil; end if b}
        Thread.new(Thread.current){|current|
          Thread.current.abort_on_exception = true
          begin
            each{|*a|}
          rescue Exception
            current.raise $!
            42
          ensure
            begin; b.call; ensure; b = nil; end if b
          end
        }
      end