Java SafeHtml collector

safeHtmlCollector.java

class xxx {
  Collector<SafeHtml, SafeHtmlBuilder, SafeHtml> safeHtmlCollector =
        Collector.of(
            SafeHtmlBuilder::new,
            (BiConsumer<SafeHtmlBuilder, SafeHtml>) SafeHtmlBuilder::append,
            (builder1, builder2) -> builder1.append(builder2.toSafeHtml()),
            SafeHtmlBuilder::toSafeHtml);
}