@Override
  public ColocationLogger start() {
    synchronized (lock) {
      if (completed.get() != null) {
        throw new IllegalStateException(this + " is already running");
      }
      completed.set(executorService.submit(checkForMissingColocatedRegionRunnable()));
      return this;
    }
  }
@param region the region that owns this logger instance
geode-core/src/main/java/org/apache/geode/internal/cache/partitioned/colocation/SingleThreadColocationLogger.java