config.ru

run ->(env) {
  blob = Random.new.bytes(1024)
  clen = 1024 * 1024
  async_body = Async::HTTP::Body::Writable.new(clen) #, queue: Async::LimitedQueue.new(4))
  Async::Reactor.run do |task|
    begin
      (clen / blob.bytesize).times { async_body.write(blob) }
    ensure
      async_body.close
    end
  end
  [200, {'Content-Length' => clen.to_s}, async_body]
}