@UnstableApi
    static WebClientBuilder builder(HttpPreprocessor httpPreprocessor, String path) {
        return new WebClientBuilder(requireNonNull(httpPreprocessor, "httpPreprocessor"),
                                    requireNonNull(path, "path"));
    }
Returns a new {@link WebClientBuilder} created with the specified {@link HttpPreprocessor}
and path.
core/src/main/java/com/linecorp/armeria/client/WebClient.java