Custom Request and APIRoute class

In some cases, you may want to override the logic used by the Request and APIRoute classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

Use cases

Automatically logging all request bodies.

IMO：特定のエンドポイントにだけ適用できるミドルウェア（ミドルウェアは全体に影響）