public static boolean isUndefinedUri(URI uri) {
        return uri == ClientUtil.UNDEFINED_URI ||
               ClientBuilderParamsUtil.UNDEFINED_URI_AUTHORITY.equals(uri.getAuthority());
    }
Returns {@code true} if the specified {@code uri} is an undefined {@link URI}, which signifies that
a {@link Client}, was created without a {@link URI} or {@link EndpointGroup}. For example,
{@code isUndefinedUri(WebClient.of().uri())} will return {@code true}.
core/src/main/java/com/linecorp/armeria/client/Clients.java