public static UnsupportedOperationException writerFormatIsForFullGraphSerializationOnly(final Class<? extends GraphWriter> clazz) {
            return new UnsupportedOperationException(String.format("%s only writes an entire Graph", clazz));
        }
Read a {@link Graph} from file using the default configuration of the {@link #reader()} and its supplied
{@link #mapper()}.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/Io.java