Use a local TCP server that doesn’t accept connections on macOS for `…

…testConnectTimeout()` (swift-server#592)

* Use a local TCP server that doesn’t accept connections on macOS for `testConnectTimeout()`

* fix linting

Call `didSendRequestPart` after the write has hit the socket (swift-s…

…erver#566)

### 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 swift-server#565.

Co-authored-by: Fabian Fett <fabianfett@apple.com>

Add link to examples folder in root README.md (swift-server#556)

Fix race between connection close and scheduling new request (swift-s…

…erver#546) (swift-server#548)

Add h2 stream integration tests (swift-server#502)

Always overwrite `Transport-Encoding` and `Content-Length` headers (s…

…wift-server#479)

Only crash in debug mode, if HTTPClient was not shutdown (swift-serve…

…r#478)

### Motivation

Generally we want to inform users that they need to shutdown their HTTPClient. Until `1.6.0` we did this with an assert in HTTPClient's deinit. With `1.6.0` this behavior was raised to a precondition. Because of this adopters might suddenly crash in production where they didn't before.

### Changes

- This pr reverts the current behavior back to something pre `1.6.0`

### Result

- HTTPClient doesn't crash in production anymore.

Support informational response heads (swift-server#469)

Don't crash when hitting long backoffs. (swift-server#458)

Motivation:

If we backoff sufficiently far we can overflow Int64, which will cause
us to crash.

Modifications:

Clamp the backoff value before we convert to Int64.

Results:

No crashes!

Always clear read idle timeout at the end of a request (swift-server#455

)