Fix Deadlock Inside Metrics Code (#105259)

Author: tarekgh

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Metrics/Instrument.cs

@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Runtime.CompilerServices;
 
 namespace System.Diagnostics.Metrics
 {
@@ -88,6 +89,17 @@ protected void Publish()
                 return;
             }
 
+            // MeterListener has a static constructor that creates runtime metrics instruments.
+            // We need to ensure this static constructor is called before starting to publish the instrument.
+            // This is necessary because creating runtime metrics instruments will cause re-entry to the Publish method,
+            // potentially resulting in a deadlock due to the SyncObject lock.
+            // Sequence of the deadlock:
+            //   1. An application creates an early instrument (e.g., Counter) before the MeterListener static constructor is executed.
+            //   2. Instrument.Publish is called and enters the SyncObject lock.
+            //   3. Within the lock block, MeterListener is called, triggering its static constructor.
+            //   4. The static constructor creates runtime metrics instruments, causing re-entry to Instrument.Publish and leading to a deadlock.
+            RuntimeHelpers.RunClassConstructor(typeof(MeterListener).TypeHandle);
+
             List<MeterListener>? allListeners = null;
             lock (Instrument.SyncObject)
             {

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Metrics/MeterListener.cs

@@ -293,7 +293,7 @@ public void Dispose()
             }
         }
 
-        // Publish is called from Instrument.Publish
+        // GetAllListeners is called from Instrument.Publish inside Instrument.SyncObject lock.
         internal static List<MeterListener>? GetAllListeners() => s_allStartedListeners.Count == 0 ? null : new List<MeterListener>(s_allStartedListeners);
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]