ApacheHttp5Client does not check if there is an 'Accept-Encoding' header when building the HttpRequest
https://github.com/OpenFeign/feign/blob/885f3e3400e564c8a4aa2642629452e9604c552e/hc5/src/main/java/feign/hc5/ApacheHttp5Client.java#L124C12-L124C12
when there is a gzip header, it should create a GzipCompressingEntity to wrap the StringEntity / ByteArrayEntity.
Because of this, the body is not compressed, while my request has an 'Accept-Encoding: gzip' header. And the server replies with a '500 Not in GZIP format' error.