Reset IncrementingPollingCounter statistics on update

Author: eterekhin

src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/CounterGroup.cs

@@ -203,7 +203,7 @@ private void ResetCounters()
                     }
                     else if (counter is IncrementingPollingCounter ipCounter)
                     {
-                        ipCounter.UpdateMetric();
+                        ipCounter.ResetStatistics();
                     }
                     else if (counter is EventCounter eCounter)
                     {

src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/IncrementingPollingCounter.cs

@@ -43,19 +43,37 @@ public IncrementingPollingCounter(string name, EventSource eventSource, Func<dou
         private double _increment;
         private double _prevIncrement;
         private readonly Func<double> _totalValueProvider;
+        private bool _resetStatistics;
+
+        internal void ResetStatistics()
+        {
+            _resetStatistics = true;
+        }
 
         /// <summary>
         /// Calls "_totalValueProvider" to enqueue the counter value to the queue.
         /// </summary>
-        internal void UpdateMetric()
+        private void UpdateMetric()
         {
-            try
+            lock (this)
             {
-                lock (this)
+                if (_resetStatistics)
                 {
-                    _prevIncrement = _increment;
-                    _increment = _totalValueProvider();
+                    UpdateMetricInternal()
+                    _resetStatistics = false;
                 }
+
+                UpdateMetricInternal();
+            }
+        }
+
+        private void UpdateMetricInternal()
+        {
+            Debug.Assert(Monitor.IsEntered(this));
+            try
+            {
+                _prevIncrement = _increment;
+                _increment = _totalValueProvider();
             }
             catch (Exception ex)
             {