### 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.
### Motivation
In the `HTTP1ConnectionStateMachine` we set the connection state to `.closed` after having forwarded an error to the inner RequestStateMachine. Since we set the state to close, the `state.modify` function did not create an action that would close the connection.
### Changes
- Modify the ConnectionState based on the RequestStateMachine's action only in the `state.modify` function.
- Add a test to verify the fixed behavior.
- Use ExpressibleByDictionaryLiteral syntax for some HTTPHeaders to increase readability.
### Result
Connections are closed, if an error happens, while we are in a request.
Fabian Fett
David Nadoba