@Override
  public int warmUpConnections(List<DataNodeId> dataNodeIds, int connectionWarmUpPercentagePerDataNode, long timeForWarmUp,
      List<ResponseInfo> responseInfoList) {
    return compNetworkClient.warmUpConnections(
        dataNodeIds, connectionWarmUpPercentagePerDataNode, timeForWarmUp, responseInfoList);
  }
Warm up connections to dataNodes in a specified time window.
@param dataNodeIds warm up target nodes.
@param connectionWarmUpPercentagePerDataNode percentage of max connections would like to establish in the warmup.
@param timeForWarmUp max time to wait for connections' establish in milliseconds.
@param responseInfoList records responses from disconnected connections.
@return number of connections established successfully.
ambry-router/src/test/java/com/github/ambry/router/MockCompositeNetworkClient.java