code: private void quiesceIngest() throws IOException {
      InjectionHandler.processEvent(InjectionEvent.STANDBY_QUIESCE_INGEST);
      synchronized (ingestStateLock) {
        assertState(StandbyIngestState.INGESTING_EDITS,
            StandbyIngestState.NOT_INGESTING);
        ingest.quiesce();
      }
      try {
        ingestThread.join();
        currentIngestState = StandbyIngestState.NOT_INGESTING;
        LOG.info("Standby: Quiesce - Ingest thread for segment: "
            + ingest.toString() + " exited.");
      } catch (InterruptedException e) {
        LOG.info("Standby: Quiesce - Ingest thread interrupted.");
        throw new IOException(e.getMessage());
      }
    }
docs: Quiesces the currently running ingest