@Nullable
    default List<LanguageRange> acceptLanguages() {
        return headers().acceptLanguages();
    }
Returns a list of {@link LanguageRange}s that are specified in {@link HttpHeaderNames#ACCEPT_LANGUAGE}
in the order of client-side preferences. If the client does not send the header, this will contain only a
wild card {@link LanguageRange}.
core/src/main/java/com/linecorp/armeria/common/HttpRequest.java