* Tolerate shutdown message after channel is closed
### Motivation
A channel can close unexpectedly if something goes wrong. We may in the meantime have scheduled the connection for graceful shutdown but the connection has not yet seen the message. We need to still accept the shutdown message and just ignore it if we are already closed.
### Modification
- ignore calls to shutdown if the channel is already closed
- add a test which would previously crash because we have transition from the closed state to the closing state and we hit the deinit precondition
- include the current state in preconditions if we are in the wrong state
### Result
We don’t hit the precondition in the deinit in the scenario described above and have more descriptive crashes if something still goes wrong.
### Motivation
Today `didSendRequestPart` is called after a request body part has been passed to the executor. However, this does not mean that the write hit the socket. Users may depend on this behavior to implement back-pressure. For this reason, we should only call this `didSendRequestPart` once the write was successful.
### Modification
Pass a promise to the actual channel write and only call the delegate once that promise succeeds.
### Result
The delegate method `didSendRequestPart` is only called after the write was successful. Fixes#565.
Co-authored-by: Fabian Fett <fabianfett@apple.com>
### Motivation
Our current swiftformat version does not support async/await. Since we want to add support for async/await we must update swiftformat or disable it. I tried my very best to keep the number of changes as small as possible. I assume we want to stick with the new 0.48.8 for some time.
### Changes
- Update swiftformat to 0.48.8
### Result
We can land async/await code.
### Motivation
Fixes#238 and #231.
### Changes
- Extracted the unclean shutdown test from `HTTPClientTests` into their own file `HTTPClientUncleanSSLConnectionShutdownTests`
- Copy and pasted @weissi great explanation from #238 into the test file
- Removed property `ignoreUncleanSSLShutdown` everywhere
### Result
`ignoreUncleanSSLShutdown` on `HTTPClient.Configuration` is deprecated and ignored.
Co-authored-by: Johannes Weiss <johannesweiss@apple.com>
- a new `RequestOptions` struct was created, that can be used to set request specific options. It is required by the `HTTPExecutableRequest`
- Added support for `ignoreUncleanSSLShutdown` in the `HTTPRequestStateMachine` and the `HTTP1ConnectionStateMachine`. In http/2 `ignoreUncleanSSLShutdown` is always off.