class Tins::Limited

def create_executor
  Thread.new do
    @mutex.synchronize do
      loop do
        if @count < @maximum
          task = @tasks.pop
          @count += 1
          Thread.new do
            @tg.add Thread.current
            task.(Thread.current)
          ensure
            @count -= 1
            @continue.signal
          end
        else
          @continue.wait(@mutex)
        end
      end
    end
  end
end