synchronized ReplicaThread.ExchangeMetadataResponse getExchangeMetadataResponse() {
    return exchangeMetadataResponse;
  }
Get the metadata response received for this replica in the most recent replication cycle.
@return exchangeMetadataResponse contains the metadata response (missing keys, token info, local lag from remote, etc.).
ambry-replication/src/main/java/com/github/ambry/replication/RemoteReplicaInfo.java