A simple way to throttle enumeration

speed_limit.rb

class SpeedLimit
  def initialize(enumerator)
    @enumerator = enumerator.to_enum
  end

  def at(count, per:)
    increment_seconds = case per
      when :second then 1.0 / count.to_f
      when :minute then 60.0 / count.to_f
      when :hour then 3600.0 / count.to_f
      else raise ArgumentError, "Expected :second, :hour, or :minute, got #{per.inspect}"
    end

    Enumerator.new do |yielder|
      loop do
        start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
        yielder.yield(@enumerator.next).tap do
          end_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
          duration = end_time - start_time
          wait = increment_seconds - duration
          Kernel.sleep wait
        end
      end
    end
  end

end

SpeedLimit.new(1..10).at(6, per: :second).each { |x| puts x }