Put a Fiber around any method using as_fiber.

as_fiber.rb

class Object
  def as_fiber(*method_names)
    method_names.each do |method_name|
      alias_method "fiberless_#{method_name}", method_name
  
      module_eval <<-eos
        def #{method_name}(*args)
          Fiber.new do
            fiberless_#{method_name}(*args)
          end.resume
        end
      eos
    end
  end
end

# Example use
class String
  as_fiber :size

end