public boolean isLeaderLessPartition(PartitionId partition) {
      return partition.getReplicaIdsByState(ReplicaState.LEADER, dataNodeId.getDatacenterName()).isEmpty();
    }
@param partition partition id
@return true if this partition doesn't have any leader in local data center.
ambry-replication/src/main/java/com/github/ambry/replication/ReplicationEngine.java