public Builder addCustom(final Class clazz, final Function<Kryo, Serializer> functionOfKryo) {
            addOrOverrideRegistration(clazz, id -> GryoTypeReg.of(clazz, id, functionOfKryo));
            return this;
        }
Register a custom class to serialize with a custom serializer as returned from a {@link Function}. Note
that calling this method for a class that is already registered will override that registration.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/gryo/GryoMapper.java