@Override
  public int warmUpConnections(List<DataNodeId> dataNodeIds, int connectionWarmUpPercentagePerDataNode,
      long timeForWarmUp, List<ResponseInfo> responseInfoList) {
    return childNetworkClients.values()
        .stream()
        .mapToInt(client -> client.warmUpConnections(dataNodeIds, connectionWarmUpPercentagePerDataNode, timeForWarmUp,
            responseInfoList))
        .sum();
  }
@param childNetworkClients a map from {@link ReplicaType} to {@link NetworkClient} to use for that type.
ambry-network/src/main/java/com/github/ambry/network/CompositeNetworkClient.java