HTTP2/bindAndHandleAsync is always returning "unknown" for extractClientIp()

https://github.com/akka/akka-http/pull/442 means that Async is not supported for clientIp? Thanks

The bug is in the way I loaded the configuration akka.http.server.remote-address-header in application.conf. However, I was using ConfigFactory.load(config).withFallback(application). The first load was silently falling back to referenceConfiguration and so my setup was lost.