Added Activity DisplayName + TraceStateString (#123)

README.md

@@ -57,6 +57,7 @@ Example of `NLog.config` file that outputs span-details together with LogEvent b
 - ParentId : Identifier for the parent activity
 - TraceId : Identifier for the root activity (Request Trace Identifier)
 - OperationName : Operation name of the current activity
+- DisplayName : Explicit assigned Activity DisplayName (with fallback to OperationName)
 - StartTimeUtc : Time when the operation started
 - Duration : Duration of the operation (formatted as TimeSpan)
 - DurationMs : Duration of the operation (formatted as TimeSpan.TotalMilliseconds)
@@ -69,6 +70,7 @@ Example of `NLog.config` file that outputs span-details together with LogEvent b
 - SourceName : Name of the activity source associated with this activity
 - SourceVersion : Version of the activity source associated with this activity
 - ActivityKind : Relationship kind between the activity, its parents, and its children. Can be combined with `format="d"`
+- TraceStateString : W3C 'tracestate' header as a string
 
 **Formatting**
 - Format: Format for rendering the property.

src/NLog.DiagnosticSource/LayoutRenderers/ActivityTraceLayoutRenderer.cs

@@ -175,6 +175,7 @@ private string GetValue(System.Diagnostics.Activity activity)
                 case ActivityTraceProperty.SpanId: return activity.GetSpanId();
                 case ActivityTraceProperty.TraceId: return activity.GetTraceId();
                 case ActivityTraceProperty.OperationName: return activity.OperationName;
+                case ActivityTraceProperty.DisplayName: return activity.DisplayName;
                 case ActivityTraceProperty.StartTimeUtc: return activity.StartTimeUtc > DateTime.MinValue ? activity.StartTimeUtc.ToString(Format, Culture) : string.Empty;
                 case ActivityTraceProperty.Duration: return GetDuration(activity);
                 case ActivityTraceProperty.ParentId: return activity.GetParentId();
@@ -186,6 +187,7 @@ private string GetValue(System.Diagnostics.Activity activity)
                 case ActivityTraceProperty.SourceName: return activity.Source?.Name;
                 case ActivityTraceProperty.SourceVersion: return activity.Source?.Version;
                 case ActivityTraceProperty.ActivityKind: return ConvertToString(activity.Kind, Format);
+                case ActivityTraceProperty.TraceStateString: return activity.TraceStateString;
                 default: return string.Empty;
             }
         }

src/NLog.DiagnosticSource/LayoutRenderers/ActivityTraceProperty.cs

@@ -73,5 +73,13 @@ public enum ActivityTraceProperty
         /// Duration of the operation (formatted as TimeSpan.TotalMilliseconds)
         /// </summary>
         DurationMs,
+        /// <summary>
+        /// Explicit assigned Activity DisplayName (with fallback to OperationName)
+        /// </summary>
+        DisplayName,
+        /// <summary>
+        /// Holds the W3C 'tracestate' header as a string. See also <see cref="System.Diagnostics.Activity.TraceStateString"/>
+        /// </summary>
+        TraceStateString,
     }
 }