@UnstableApi
    public boolean autoFillOriginHeader() {
        return get(AUTO_FILL_ORIGIN_HEADER);
    }
Returns whether to add an {@link HttpHeaderNames#ORIGIN} header automatically when sending
an {@link HttpRequest} when the {@link HttpRequest#headers()} does not have it.
core/src/main/java/com/linecorp/armeria/client/ClientOptions.java