Previously, the `NotFound` status code was used to signal many kinds of
recoverable, forwarding errors. This included validation errors, incorrect
Content-Type errors, and more.
This commit modifies the status code used to forward in these instances to more
precisely indicate the forwarding condition. In particular:
* Parameter `FromParam` errors now forward as 422 (`UnprocessableEntity`).
* Query paramater errors now forward as 422 (`UnprocessableEntity`).
* Use of incorrect form content-type forwards as 413 (`UnsupportedMediaType`).
* `WebSocket` guard now forwards as 400 (`BadRequest`).
* `&Host`, `&Accept`, `&ContentType`, `IpAddr`, and `SocketAddr` all forward
with a 500 (`InternalServerError`).
Additionally, the `IntoOutcome` trait was overhauled to support functionality
previously offered by methods on `Outcome`. The `Outcome::forward()` method now
requires a status code to use for the forwarding outcome.
Finally, logging of `Outcome`s now includes the relevant status code.
Resolves#2626.
Prior to this commit, all forward outcomes resulted in a 404. This
commit changes request and data guards so that they are able to provide
a `Status` on `Forward` outcomes. The router uses this status, if the
final outcome is to forward, to identify the catcher to invoke.
The net effect is that guards can now customize the status code of a
forward and thus the error catcher invoked if the final outcome of a
request is to forward.
Resolves#1560.
This modifies the 'IoHandler::io()' method so that it takes a
'Pin<Box<Self>>', allowing handlers to move internally and assume that
the data is pinned.
The change is then used in the 'ws' contrib crate to allow 'FnOnce'
handlers instead of 'FnMut'. The net effect is that streams, such as
those crated by 'Stream!', are now allowed to move internally.