private BucketMembershipObserver beginMonitoring() {
      int profilesPresent = bucketToMonitor.getBucketAdvisor()
          .addMembershipListenerAndAdviseGeneric(this).size();
      arrivals.addAndGet(profilesPresent);
      return this;
    }
Monitors distributed membership for a given bucket
geode-core/src/main/java/org/apache/geode/internal/cache/PRHARedundancyProvider.java