public class TraceArgument 

IReadOnlyList<Element> startingPointList = new List<Element>();

// Code to fill in list of starting points goes here...
TraceArgument traceArgument = new TraceArgument(startingPointList);

TraceConfiguration traceConfiguration = new TraceConfiguration();

// Code to fill in trace configuration goes here...
traceArgument.Configuration = traceConfiguration;

private void TraceWithDigitizedDirection(UtilityNetwork utilityNetwork, Element startElement)
{
  using TraceManager traceManager = utilityNetwork.GetTraceManager();

  // Trace configuration with digitized direction 
  TraceConfiguration traceConfiguration = new TraceConfiguration()
  {
    IncludeIsolatedFeatures = true,
    IncludeBarriersWithResults = true,
    UseDigitizedDirection = true
  };

  // Trace argument
  List<Element> startElements = new List<Element> { startElement };

  TraceArgument traceArgument = new TraceArgument(startElements);
  traceArgument.Configuration = traceConfiguration;

  // Results
  DownstreamTracer downstreamTracer = traceManager.GetTracer<DownstreamTracer>();

  IReadOnlyList<Result> traceResults = downstreamTracer.Trace(traceArgument);
  foreach (Result traceResult in traceResults)
  {
    // Iterate trace results
  }
}