    # File lib/amqp/int_allocator.rb, line 27
        def initialize(lo, hi)
          raise ArgumentError.new "upper boundary must be greater than the lower one (given: hi = #{hi}, lo = #{lo})" unless hi > lo

          @hi = hi
          @lo = lo

          @number_of_bits = hi - lo
          @range          = Range.new(1, @number_of_bits)
          @free_set       = BitSet.new(@number_of_bits)
        end