public boolean isSharable() {
        final Class<?> clazz = getClass();
        Boolean sharable = cache.get(clazz);
        if (sharable == null) {
            sharable = clazz.isAnnotationPresent(Sharable.class);
            cache.put(clazz, sharable);
        }
        return sharable;
    }
Return {@code true} if the implementation is {@link Sharable} and so can be added
to different {@link Pipeline}s.
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/util/pipeline/HandlerAdapter.java