public class CIMSimpleLineCallout : CIMCallout, System.ComponentModel.INotifyPropertyChanged, System.Xml.Serialization.IXmlSerializable  

/// <summary>
/// Creates a simple line callout text symbol.  The [CIMSimpleLineCallout](https://pro.arcgis.com/en/pro-app/sdk/api-reference/#topic2760.html) created is a dash-dot-dash line symbol with an offset of 10 from the geometry being labeled.
/// ![lineCallOut](https://ArcGIS.github.io/arcgis-pro-sdk/images/Labeling/line-callout.png)
/// </summary>
{
  //create a text symbol
  //Note: Run this code inside a QueuedTask
  var textSymbolCallOut = SymbolFactory.Instance.ConstructTextSymbol(ColorFactory.Instance.BlackRGB, 10, "Verdana", "Regular");
  //Create a line call out
  var lineCalloutSymbol = new CIMSimpleLineCallout();
  //Get a line symbol
  var lineSymbol = SymbolFactory.Instance.ConstructLineSymbol(ColorFactory.Instance.BlackRGB, 1, SimpleLineStyle.DashDotDot);
  //assign the line symbol to the callout
  lineCalloutSymbol.LineSymbol = lineSymbol;
  //Offset for the text
  textSymbolCallOut.OffsetX = 10;
  textSymbolCallOut.OffsetY = 10;
  //Assign the callout to the text symbol
  textSymbolCallOut.Callout = lineCalloutSymbol;

  //Refer to the snippet "How to apply a Text Symbol to labels of a layer" below to see how to apply this text symbol to a label class
}