@FeatureDescriptor(name = FEATURE_IO_READ)
            default boolean supportsIoRead() {
                return true;
            }
Determines if the {@code Graph} implementations supports read operations as executed with the
{@link GraphTraversalSource#io(String)} step. Graph implementations will generally support this by
default as any graph that can support direct mutation through the Structure API will by default
accept data from the standard TinkerPop {@link GraphReader} implementations. However, some graphs like
{@code HadoopGraph} don't accept direct mutations but can still do reads from that {@code io()} step.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/Graph.java