@Override
    public void onPartitionBecomeLeaderFromStandby(String partitionName) {
      logger.info("Partition state change notification from Standby to Leader received for partition {}",
          partitionName);
      if (leaderBasedReplicationAdmin != null) {
        // Add the leader partition (and its peer leaders) information to the in-mem structure maintained in
        // leaderBasedReplicationAdmin. LeaderBasedReplicationAdmin::addLeaderPartition is thread safe.
        leaderBasedReplicationAdmin.addLeaderPartition(partitionName);
      }
    }
{@link PartitionStateChangeListener} to capture changes in partition state.
ambry-replication/src/main/java/com/github/ambry/replication/ReplicationManager.java