There are cases where I explicitly want to return 503.

[pyama86]

Async.subrequestを利用する際に、すぐに503を返したいケースなどがあり、対応できていなかったので、Nginx::DECLINE、Nginx::OK以外のときは即レスポンスを返すようにします。

Pull-Request Check List

• [x] Add patches into src/.
• [x] Add test into test/. Please see about test docs.
• [x] Add docs into docs/ if you change the features such as build system, Ruby methods, class and nginx directives.

[matsumotory]

Thanks!