public new RealtimeFeatureClass GetFeatureClass()

//Must be on QueuedTask!
//Must be called on the feature class
using (var rfc = streamLayer.GetFeatureClass())
  rfc.Truncate();

await QueuedTask.Run(async () =>
{
  //query filter can be null to search and retrieve all rows
  //true means recycling cursor
  using (var rc = streamLayer.SearchAndSubscribe(qfilter, true))
  {
    //waiting for new features to be streamed
    //default is no cancellation
    while (await rc.WaitForRowsAsync())
    {
      while (rc.MoveNext())
      {
        using (var row = rc.Current)
        {
          //determine the origin of the row event
          switch (row.GetRowSource())
          {
            case RealtimeRowSource.PreExisting:
              //pre-existing row at the time of subscribe
              continue;
            case RealtimeRowSource.EventInsert:
              //row was inserted after subscribe
              continue;
            case RealtimeRowSource.EventDelete:
              //row was deleted after subscribe
              continue;
          }
        }
      }
    }
  }//row cursor is disposed. row cursor is unsubscribed

  //....or....
  //Use the feature class instead of the layer
  using (var rfc = streamLayer.GetFeatureClass())
  {
    //non-recycling cursor - 2nd param "false"
    using (var rc = rfc.SearchAndSubscribe(qfilter, false))
    {
      //waiting for new features to be streamed
      //default is no cancellation
      while (await rc.WaitForRowsAsync())
      {
        //etc
      }
    }
  }
});

await QueuedTask.Run(async () =>
{
  //Recycling cursor - 2nd param "true"
  //or streamLayer.Subscribe(qfilter, true) to just subscribe
  using (var rc = streamLayer.SearchAndSubscribe(qfilter, true))
  {
    //auto-cancel after 20 seconds
    var cancel = new CancellationTokenSource(new TimeSpan(0, 0, 20));
    //catch TaskCanceledException
    try
    {
      while (await rc.WaitForRowsAsync(cancel.Token))
      {
        //check for row events
        while (rc.MoveNext())
        {
          using (var row = rc.Current)
          {
            //etc
          }
        }
      }
    }
    catch (TaskCanceledException )
    {
      //Handle cancellation as needed
    }
    cancel.Dispose();
  }
});

using (var rfc = streamLayer.GetFeatureClass())
using (var rfc_def = rfc.GetDefinition())
{
  if (rfc_def.HasTrackIDField())
  {
    //Track aware
  }
}

//Must be on QueuedTask
using (var rfc = streamLayer.GetFeatureClass())
using (var rfc_def = rfc.GetDefinition())
{
  if (rfc_def.HasTrackIDField())
  {
    var fld_name = rfc_def.GetTrackIDField();

  }
}