def max=(m)
      m = m.to_i
      raise ArgumentError.new('Maximum value must be greater than 0') unless m > 0
      @max_threads = m
      @min_threads = m if m < @min_threads
      resize if m < size
      m
    end
def max=(m)
      m = m.to_i
      raise ArgumentError.new('Maximum value must be greater than 0') unless m > 0
      @max_threads = m
      @min_threads = m if m < @min_threads
      resize if m < size
      m
    end
m:: new max
 Set maximum number of threads