@Override
        public Io create() {
            calledCreate++;
            return mock(Io.class);
        }
Coerces a {@code Color} to a {@link TinkerGraph} during serialization.  Demonstrates how custom serializers
can be developed that can coerce one value to another during serialization.
tinkergraph-gremlin/src/test/java/org/apache/tinkerpop/gremlin/tinkergraph/structure/TinkerGraphTest.java