private List<NetworkClientDelegate.FutureCompletionHandler> assertPoll(
        final int numRes,
        final CommitRequestManager manager) {
        return assertPoll(true, numRes, manager);
    }
@return Retriable coordinator errors and a boolean indicating if it is expected to mark
the coordinator unknown when the error occurs.
clients/src/test/java/org/apache/kafka/clients/consumer/internals/CommitRequestManagerTest.java