public InternalDistributedMember getPrimaryMemberForBucket(int bucketId) {
    Bucket b = buckets[bucketId];
    return b.getBucketAdvisor().getPrimary();
  }
Get the most recent primary node for the bucketId. Returns null if no primary can be found
within {@link DistributionConfig#getMemberTimeout}.

@return the Node managing the primary copy of the bucket
geode-core/src/main/java/org/apache/geode/internal/cache/partitioned/RegionAdvisor.java