@Override
  public void regionReinitializing(String fullPath) {
    Object old = reinitializingRegions.putIfAbsent(fullPath, new FutureResult<>(stopper));
    if (old != null) {
      throw new IllegalStateException(
          String.format("Found an existing reinitializing region named %s",
              fullPath));
    }
  }
Return true if the region is initializing.
geode-core/src/main/java/org/apache/geode/internal/cache/GemFireCacheImpl.java