This is needed to make optimizations possible.
e.g. the id-,name-, class-attribute values are not needed to be HTML escaped. But the interface ResponseWriter doesn't allow to write without closing the startElement-tag.
The Tobago renderers may call
OptimizedResponseWriter writer = HtmlRendererUtil.getOptimizedResponseWriter(facesContext);
to get a writer. The static method getOptimizedResponseWriter() may return the TobagoResponseWriter which implements the OptimizedResponseWriter or otherwize return a wrapped object of the given ResponseWriter.
The new OptimizedResponseWriterWrapper class is not optimized, because of the closing-of-the-startElement restriction.
Remove automatical check of needed escaping from TobagoResponseWriter. Special id-, name-, class-attribute setter should be called.