class Restforce::Configuration::Option

def define_method
  our_default = default
  our_name    = name
  configuration.send :define_method, our_name do
    instance_variable_get(:"@#{our_name}") ||
      instance_variable_set(
        :"@#{our_name}",
        our_default.respond_to?(:call) ? our_default.call : our_default
      )
  end
end