private ExecutorService createScanExecutor(Id.Stream streamId) {
   ThreadFactory threadFactory =
       Threads.newDaemonThreadFactory(
           String.format(
               "stream-%s-%s-consumer-scanner-", streamId.getNamespaceId(), streamId.getId()));
   ThreadPoolExecutor executor =
       new ThreadPoolExecutor(
           1, 20, 60, TimeUnit.SECONDS, new SynchronousQueue<Runnable>(), threadFactory);
   executor.allowCoreThreadTimeOut(true);
   return executor;
 }