4892436efe
This commit refactors the `ClientHttpRequestFactory` into an `ClientHttpConnector` abstraction, in order to reflect that `ClientHttpRequest`s only "exist" once the client is connected to the origin server. This is why the HTTP client is now callback-based, containing all interactions with the request within a `Function<ClientHttpRequest,Mono<Void>>` that signals when it's done writing to the request. The `ClientHttpRequest` contract also adopts `setComplete()` and promotes that method to the `ReactiveHttpOutputMessage` contract. This commit also adapts all other APIs to that change and fixes a few issues, including: * use `HttpMessageConverter`s instead of `Encoders`/`Decoders` * better handle type information about request content publishers * support client cookies in HTTP requests * temporarily remove the RxNetty client support