synchronized boolean deferCrfDelete(Oplog oplog) {
    if (pendingBackup.contains(oplog)) {
      deferredCrfDeletes.add(oplog);
      return true;
    }

    return false;
  }
Add the oplog to the list of deferred deletes.

@return true if the delete has been deferred. False if this oplog should be deleted
        immediately.
geode-core/src/main/java/org/apache/geode/internal/cache/backup/DiskStoreBackup.java