// instance
configure(pipeline);
pipeline.addLast(PIPELINE_OP_SELECTOR, new OpSelectorHandler(settings, graphs, gremlinExecutor, scheduledExecutorService));
pipeline.addLast(gremlinGroup, PIPELINE_RESULT_ITERATOR_HANDLER, new IteratorHandler(settings));
pipeline.addLast(gremlinGroup, PIPELINE_OP_EXECUTOR, new OpExecutorHandler(settings, graphs, gremlinExecutor, scheduledExecutorService));
finalize(pipeline);
}