Try will check if "fn" ran without any panics, using recovery, and return its result as the final response otherwise it returns the "failure" response if any, if not then a 400 bad request is being sent.

DefaultViewExt is the default extension if `view.Name `is missing, but note that it doesn't care about the app.RegisterView(iris.$VIEW_ENGINE("./$dir", "$ext"))'s $ext.

C is the lightweight BaseController type as an alternative of the `Controller` struct type.

Controller is the base controller for the high level controllers instances.

Response completes the `methodfunc.Result` interface.

SessionController is a simple `Controller` implementation which requires a binded session manager in order to give direct access to the current client's session via its `Session` field.

View completes the `methodfunc.Result` interface.

Result is a response dispatcher.