ractor_mutex.rb

mut = Ractor.new do
  pipe = Ractor.new do
    loop { Ractor.yield Ractor.receive }
  end
  loop do
    Ractor.yield pipe
    pipe.take
  end
end

def mut.synchronize
  r = take
  yield
ensure
  r.send :synchronize_end
end

ractors = 100.times.map do |n|
  Ractor.new(mut,n) do |mut,n|
    2.times do
      mut.synchronize do
        p n => :start
        sleep 0.01
        p n => :end
      end
    end
  end
end
ractors.map(&:take)