@Test
    @LoadGraphWith(LoadGraphWith.GraphData.CLASSIC)
    public void shouldReadWriteVerticesNoEdgesToGryoManual() throws Exception {
        assumeThat(ioType, is("gryo"));
        try (final ByteArrayOutputStream os = new ByteArrayOutputStream()) {
            final GraphWriter writer = writerMaker.apply(graph);
            writer.writeVertices(os, g.V().has("age", P.gt(30)));

            final AtomicInteger called = new AtomicInteger(0);
            final GraphReader reader = readerMaker.apply(graph);
            try (final VertexByteArrayInputStream vbais = new VertexByteArrayInputStream(new ByteArrayInputStream(os.toByteArray()))) {
                final byte[] y = vbais.readVertexBytes().toByteArray();
                reader.readVertex(new ByteArrayInputStream(y),
                        attachable -> {
                            final Vertex detachedVertex = attachable.get();
                            called.incrementAndGet();
                            return detachedVertex;
                        });

                final byte[] z = vbais.readVertexBytes().toByteArray();
                reader.readVertex(new ByteArrayInputStream(z),
                        attachable -> {
                            final Vertex detachedVertex = attachable.get();
                            called.incrementAndGet();
                            return detachedVertex;
                        });
            }

            assertEquals(2, called.get());
        }
    }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/structure/io/IoVertexTest.java