Introduce Activity.IsStopped Property

src/libraries/System.Diagnostics.DiagnosticSource/ref/System.Diagnostics.DiagnosticSourceActivity.cs

@@ -25,6 +25,7 @@ public string? Id
         }
 
         public bool IsAllDataRequested { get { throw null; } set { throw null; } }
+        public bool IsStopped { get { throw null; } }
         public System.Diagnostics.ActivityIdFormat IdFormat { get { throw null; } }
         public System.Diagnostics.ActivityKind Kind  { get { throw null; } }
         public string OperationName { get { throw null; } }

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Activity.cs

@@ -784,6 +784,11 @@ public ActivityTraceId TraceId
         /// </summary>
         public bool IsAllDataRequested { get; set;}
 
+        /// <summary>
+        /// Indicate if the this Activity object is stopped
+        /// </summary>
+        public bool IsStopped { get => IsFinished; }
+
         /// <summary>
         /// Return the flags (defined by the W3C ID specification) associated with the activity.
         /// </summary>

src/libraries/System.Diagnostics.DiagnosticSource/tests/ActivityTests.cs

@@ -299,7 +299,6 @@ public void ActivityIdOverflow()
             Assert.Equal('#', activity.Id[activity.Id.Length - 1]);
         }
 
-
         /// <summary>
         /// Tests activity start and stop
         /// Checks Activity.Current correctness, Id generation
@@ -320,6 +319,31 @@ public void StartStop()
             Assert.Null(Activity.Current);
         }
 
+        /// <summary>
+        /// Tests Activity.IsStopped
+        /// </summary>
+        [Fact]
+        public void IsStoppedTest()
+        {
+            var activity = new Activity("activity");
+            Assert.False(activity.IsStopped);
+            activity.Start();
+            Assert.False(activity.IsStopped);
+            Assert.Equal(TimeSpan.Zero, activity.Duration);
+            activity.Stop();
+            Assert.NotEqual(TimeSpan.Zero, activity.Duration);
+            Assert.True(activity.IsStopped);
+
+            activity = new Activity("activity");
+            Assert.False(activity.IsStopped);
+            activity.Start();
+            Assert.False(activity.IsStopped);
+            activity.SetEndTime(DateTime.UtcNow.AddMinutes(1)); // Setting end time shouldn't mark the activity as stopped
+            Assert.False(activity.IsStopped);
+            activity.Stop();
+            Assert.True(activity.IsStopped);
+        }
+
         /// <summary>
         /// Tests Id generation
         /// </summary>