@Override
    public String toString() {
      return "StateMarkerMessage(requestingMember=" + getSender() + ",processorId="
          + processorId + ",target=" + relayRecipient + ",region=" + regionPath + ")";
    }
returns a set of all DistributedRegions for allRegions processing
geode-core/src/main/java/org/apache/geode/internal/cache/StateFlushOperation.java