private DistributedMember getMember(DistributedMember mbr) {
    if (mbr == null) {
      return cache.getInternalDistributedSystem().getDistributedMember();
    } else {
      return null;
    }
  }
return the argument, or if null the DistributedMember id of this vm
geode-core/src/main/java/org/apache/geode/cache/DynamicRegionFactory.java