@Override
    @SuppressWarnings("unchecked")
    protected <T> HasSchema<T> transferPojoId(Input input, Output output,
            int fieldNumber) throws IOException
    {
        final int id = input.readUInt32();

        final BaseHS<T> wrapper = (BaseHS<T>) pojos.get(id);
        if (wrapper == null)
            throw new UnknownTypeException("pojo id: " + id + " (Outdated registry)");

        output.writeUInt32(fieldNumber, id, false);

        return wrapper;
    }
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