A port of the Crystal "skynet" code to Ruby, see https://bugs.ruby-lang.org/issues/18760

skynet.rb

require 'async'
require 'async/queue'

def skynet(c, num, size, div)
  if size == 1
    c << num
  else
    rc = Async::LimitedQueue.new(div)
    sum = 0
    div.times do |i|
      sub_num = num + (i * (size / div))
      Async { skynet(rc, sub_num, size / div, div) }
    end
    div.times do
      sum += rc.dequeue
    end
    c << sum
  end
end

c = Async::LimitedQueue.new(1)
start_time = Time.now
Sync { skynet(c, 0, 1_000_000, 10) }
result = Sync { c.dequeue }
end_time = Time.now
puts "Result: #{result} in #{end_time - start_time}s."