@Nullable
    @Override
    public final <U> U as(Class<U> type) {
        final U result = Unwrappable.super.as(type);
        return result != null ? result : delegate.as(type);
    }
Creates a new decorator with the specified delegate.
core/src/main/java/com/linecorp/armeria/common/util/AbstractUnwrappable.java