Channel select unwait benchmark

bench.cr

ch1 = Channel(Int32).new
ch2 = Channel(Int32).new

500.times do 
  spawn do
    r = Random.new
    ch2.send(r.next_int)
  end
end

spawn do
  loop do
    ch1.receive
  end
end

total_delay = Time::Span::ZERO

(ARGV[0]? || 1000).to_i.times do
  total_delay += Time.measure do
    select
    when ch1.send 1
    when ch2.send 2
    end
  end
end

puts total_delay