class Puma::Rack::Builder

def warmup(prc=nil, &block)

run MyApp
use SomeMiddleware

end
client.get('/')
client = Rack::MockRequest.new(app)
warmup do |app|

Takes a lambda or block that is used to warm-up the application.
def warmup(prc=nil, &block)
  @warmup = prc || block
end