Tokio's `File::write_all()` method has an unexpected quirk: it doesn't
actually write all the requested content to the file when the returned
future resolves. Instead, the write is attempted and queued. This means
that the `persist()` method can resolve without the data being persisted
to the file system. Subsequent reads of the ostensibly written-to file
can thus fail to contain the expected data.
An call to `flush()` following `write_all()` would circumvent the issue.
Alternatively, calling `fs::write()` actually writes to the file system
before returning and requires fewer lines of code. This commit thus
swaps the call to `write_all()` with `fs::write()`.
In the process, the following improvements were also made:
* Error messages related to TLS were improved.
* 'Redirector' in 'tls' example was improved.
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.
The primary motivation is to deconflate the leading `F`s in `Failure` and
`Forward`. In particular, when using a generics, we used `F` for forward, which
could easily be confused for `F` for `Failure`. This resolves the conflation.