@After
  public void after() {
    nettyByteBufLeakHelper.afterTest();
  }
Running for the two sets of compatible ReplicaMetadataRequest and ReplicaMetadataResponse,
viz {{@code ReplicaMetadataRequest#Replica_Metadata_Request_Version_V1}, {@code ReplicaMetadataResponse#REPLICA_METADATA_RESPONSE_VERSION_V_5}}
& {{@code ReplicaMetadataRequest#Replica_Metadata_Request_Version_V2}, {@code ReplicaMetadataResponse#REPLICA_METADATA_RESPONSE_VERSION_V_6}}
@return an array with both pairs of compatible request and response.
ambry-replication/src/test/java/com/github/ambry/replication/ReplicationTest.java