@Override
  public RealizationResult delete(Region config, InternalCache cache) {
    org.apache.geode.cache.Region region = cache.getRegion(config.getName());
    if (region == null) {
      // Since we are trying to delete this region, we can return early
      return new RealizationResult().setMessage("Region does not exist.");
    }

    try {
      region.destroyRegion();
    } catch (RegionDestroyedException dex) {
      // Probably happened as a distributed op but it still reflects our current desired action
      // which is why it can be ignored here.
      return new RealizationResult().setMessage("Region does not exist.");
    }
    return new RealizationResult().setMessage("Region successfully deleted.");
  }
the default implementation will have the extra work of getting the runtime info which is
unnecessary. It will also have some concurrency issue if the region is being destroyed.
geode-core/src/main/java/org/apache/geode/management/internal/configuration/realizers/RegionConfigRealizer.java