private static void chooseConnections(int operations, Client.ClusteredClient client, ExecutorService executorServiceForTesting) throws InterruptedException {
        final RequestMessage.Builder request = client.buildMessage(RequestMessage.build("g.inject(1)"));
        final Callable<Connection> sendQueryCallable = () -> client.chooseConnection(request.create());
        final List<Callable<Connection>> listOfTasks = new ArrayList<>();
        for (int i = 0; i < operations; i++) {
            listOfTasks.add(sendQueryCallable);
        }

        final List<Future<Connection>> executorSubmitFutures = executorServiceForTesting.invokeAll(listOfTasks);
        executorSubmitFutures.parallelStream().map(fut -> {
            try {
                return fut.get();
            } catch (InterruptedException | ExecutionException e) {
                fail(e.getMessage());
                return null;
            }
        }).forEach(Assert::assertNotNull);
    }
Added for TINKERPOP-2813 - this scenario would have previously thrown tons of
{@link NoHostAvailableException}.
gremlin-server/src/test/java/org/apache/tinkerpop/gremlin/driver/ClientConnectionIntegrateTest.java