@Override
    public void clear() {
        setOwned(null);
    }
Default implementation of {@link BuilderRef}.

<p>This class is not threadsafe; it should only be used to build up
other objects using {@link #copy()}.

@param <T> The type of value being built, borrowed, and copied.
smithy-utils/src/main/java/software/amazon/smithy/utils/DefaultBuilderRef.java