public Function<? super Endpoint, ? extends EndpointGroup> endpointRemapper() {
        return get(ENDPOINT_REMAPPER);
    }
Returns the {@link Function} that remaps a target {@link Endpoint} into an {@link EndpointGroup}.

@see ClientBuilder#endpointRemapper(Function)
core/src/main/java/com/linecorp/armeria/client/ClientOptions.java