config.ru

# frozen_string_literal: true

code = 200
headers = {'content-type' => 'text/plain'}.freeze
body = lambda do |stream|
  clock = %w[tick tock].cycle
  42.times do
    stream.write clock.next
    stream.write "\n"
    sleep 1
  end
  stream.close
end.freeze

run ->(_env) { [code, headers, body] }.freeze

Gemfile

# frozen_string_literal: true

source 'https://rubygems.org'

gem 'rack', github: 'rack/rack'
gem 'puma', github: 'puma/puma'

streaming.sh

ruby -rhttp -e "HTTP.get('http://0.0.0.0:9292').body.each { |message| print message }"