public CompletableFuture<Void> allItemsAvailableAsync() {
        // readCompleted future is always completed by Netty's event loop thread pool. To avoid blocking the event loop,
        // create a new completion stage that is completed by executor thread loop, when returning a future outside the
        // client (ie application code).
        return readCompleted.whenCompleteAsync((s,t) -> {}, executor);
    }
Returns a future that will complete when all items have been returned from the server.
gremlin-driver/src/main/java/org/apache/tinkerpop/gremlin/driver/ResultSet.java