@Override
        public void serialize(final CustomId customId, final JsonGenerator jsonGenerator, final SerializerProvider serializerProvider)
                throws IOException, JsonGenerationException {
            final Map<String, Object> m = new HashMap<>();
            m.put("cluster", customId.getCluster());
            m.put("elementId", customId.getElementId());
            jsonGenerator.writeObject(m);
        }
A mock identifier for use in ensuring that custom serializers work around element identifiers.

@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/structure/io/util/CustomId.java