static WebClientBuilder builder(URI uri) {
        return new WebClientBuilder(uri);
    }
Returns a new {@link WebClientBuilder} created with the specified base {@link URI}.

@throws IllegalArgumentException if the {@code uri} is not valid or its scheme is not one of the values
                                 in {@link SessionProtocol#httpValues()} or
                                 {@link SessionProtocol#httpsValues()}.
core/src/main/java/com/linecorp/armeria/client/WebClient.java