public DistributionManager getDistributionManager() {
    GfManagerAgent agent = gfManagerAgent;
    if (agent == null) {
      return null;
    }
    return agent.getDM();
  }
Returns the DistributionManager this implementation is using to connect to the distributed
system.
geode-core/src/main/java/org/apache/geode/admin/internal/AdminDistributedSystemImpl.java