code: public void startSyncPostJournal(AlluxioURI uri) throws InvalidPathException {
      MountTable.Resolution resolution = mMountTable.resolve(uri);
      startInitSync(uri, resolution);
      launchPollingThread(resolution.getMountId(), SyncInfo.INVALID_TXID);
    }
docs: Continue to start sync after we have journaled the operation.
  
  @param uri the sync point that we are trying to start