private int collectionId(Class<?> clazz)
    {
        final RegisteredCollectionFactory factory = collectionMapping.get(clazz);
        if (factory == null)
            throw new UnknownTypeException("collection: " + clazz);

        return (factory.id << 5) | CID_COLLECTION;
    }
Register a {@link Delegate} and assign an id.
<p>
Delegate ids start at 1.
protostuff-runtime-registry/src/main/java/io/protostuff/runtime/ExplicitIdStrategy.java