public abstract class Function 

// Get a NetworkAttribute object for the Load network attribute from the UtilityNetworkDefinition
using (NetworkAttribute loadNetworkAttribute = utilityNetworkDefinition.GetNetworkAttribute("Load"))
{
  // Create a function to sum the Load
  Add sumLoadFunction = new Add(loadNetworkAttribute);

  // Add this function to our trace configuration
  traceConfiguration.Functions = new List<Function>() { sumLoadFunction };
}

// Create a NetworkAttribute object for the Shape length network attribute from the UtilityNetworkDefinition
using (NetworkAttribute shapeLengthNetworkAttribute = utilityNetworkDefinition.GetNetworkAttribute("Shape length"))
{
  // Create a function that adds up shape length
  Add lengthFunction = new Add(shapeLengthNetworkAttribute);

  // Create a function barrier that stops traversal after 1000 feet
  FunctionBarrier distanceBarrier = new FunctionBarrier(lengthFunction, Operator.GreaterThan, 1000.0);

  // Set this function barrier
  traceConfiguration.Traversability.FunctionBarriers = new List<FunctionBarrier>() { distanceBarrier };
}