private void checkSenderStillAlive(PartitionedRegion r, InternalDistributedMember sender) {
    if (!r.getDistributionAdvisor().containsId(sender)) {
      r.getRedundancyProvider().finishIncompleteBucketCreation(bucketId);
    }
  }
Check that sender is still a participant in the partitioned region. If not, notify other nodes
to create backup buckets
geode-core/src/main/java/org/apache/geode/internal/cache/partitioned/ManageBucketMessage.java