Improve descriptions

Author: pavelsavara

src/Components/Components/src/ComponentsMetrics.cs

@@ -44,19 +44,19 @@ public ComponentsMetrics(IMeterFactory meterFactory)
         _eventDuration = _meter.CreateHistogram(
             "aspnetcore.components.event_handler",
             unit: "s",
-            description: "Duration of processing browser event.",
+            description: "Duration of processing browser event.  It includes business logic of the component but not affected child components.",
             advice: new InstrumentAdvice<double> { HistogramBucketBoundaries = MetricsConstants.ShortSecondsBucketBoundaries });
 
         _parametersDuration = _lifeCycleMeter.CreateHistogram(
             "aspnetcore.components.update_parameters",
             unit: "s",
-            description: "Duration of processing component parameters.",
+            description: "Duration of processing component parameters. It includes business logic of the component.",
             advice: new InstrumentAdvice<double> { HistogramBucketBoundaries = MetricsConstants.BlazorRenderingSecondsBucketBoundaries });
 
         _batchDuration = _lifeCycleMeter.CreateHistogram(
             "aspnetcore.components.render_diff",
             unit: "s",
-            description: "Duration of rendering DOM update including network and browser time.",
+            description: "Duration of rendering component tree and producing HTML diff. It includes business logic of the changed components.",
             advice: new InstrumentAdvice<double> { HistogramBucketBoundaries = MetricsConstants.BlazorRenderingSecondsBucketBoundaries });
     }
 

src/Components/Components/src/RenderTree/Renderer.cs

@@ -450,10 +450,12 @@ public virtual Task DispatchEventAsync(ulong eventHandlerId, EventFieldInfo? fie
 
         // collect trace
         Activity? activity = null;
+        string receiverName = null;
+        string methodName = null;
         if (ComponentActivitySource != null)
         {
-            var receiverName = (callback.Receiver?.GetType() ?? callback.Delegate.Target?.GetType())?.FullName;
-            var methodName = callback.Delegate.Method?.Name;
+            receiverName ??= (callback.Receiver?.GetType() ?? callback.Delegate.Target?.GetType())?.FullName;
+            methodName ??= callback.Delegate.Method?.Name;
             activity = ComponentActivitySource.StartEventActivity(receiverName, methodName, attributeName);
         }
 
@@ -503,8 +505,8 @@ public virtual Task DispatchEventAsync(ulong eventHandlerId, EventFieldInfo? fie
             // collect metrics
             if (ComponentMetrics != null && ComponentMetrics.IsEventEnabled)
             {
-                var receiverName = (callback.Receiver?.GetType() ?? callback.Delegate.Target?.GetType())?.FullName;
-                var methodName = callback.Delegate.Method?.Name;
+                receiverName ??= (callback.Receiver?.GetType() ?? callback.Delegate.Target?.GetType())?.FullName;
+                methodName ??= callback.Delegate.Method?.Name;
                 _ = ComponentMetrics.CaptureEventDuration(task, eventStartTimestamp, receiverName, methodName, attributeName);
             }
 
@@ -518,8 +520,8 @@ public virtual Task DispatchEventAsync(ulong eventHandlerId, EventFieldInfo? fie
         {
             if (ComponentMetrics != null && ComponentMetrics.IsEventEnabled)
             {
-                var receiverName = (callback.Receiver?.GetType() ?? callback.Delegate.Target?.GetType())?.FullName;
-                var methodName = callback.Delegate.Method?.Name;
+                receiverName ??= (callback.Receiver?.GetType() ?? callback.Delegate.Target?.GetType())?.FullName;
+                methodName ??= callback.Delegate.Method?.Name;
                 ComponentMetrics.FailEventSync(e, eventStartTimestamp, receiverName, methodName, attributeName);
             }