feat(telemetry): ensure deterministic EventSource construction

Author: BenjaminAbt

src/HttpUserAgentParser.AspNetCore/Telemetry/HttpUserAgentParserAspNetCoreTelemetry.cs

@@ -73,6 +73,8 @@ public static bool AreMetersEnabled
     /// </summary>
     public static void Enable()
     {
+        // Force EventSource construction at enable-time so listeners can subscribe deterministically.
+        // This avoids CI-only timing races where first telemetry events happen before listener attachment.
         _ = HttpUserAgentParserAspNetCoreEventSource.Log;
         Interlocked.Or(ref s_enabledFlags, EventCountersFlag);
     }

src/HttpUserAgentParser.MemoryCache/Telemetry/HttpUserAgentParserMemoryCacheTelemetry.cs

@@ -54,6 +54,8 @@ public static bool IsCacheSizeEnabled
     /// </summary>
     public static void Enable()
     {
+        // Force EventSource construction at enable-time so listeners can subscribe deterministically.
+        // This avoids CI-only timing races where first telemetry events happen before listener attachment.
         _ = HttpUserAgentParserMemoryCacheEventSource.Log;
         Interlocked.Or(ref s_enabledFlags, EventCountersFlag);
     }

src/HttpUserAgentParser/Telemetry/HttpUserAgentParserTelemetry.cs

@@ -62,6 +62,8 @@ public static bool IsCacheSizeEnabled
     /// </summary>
     public static void Enable()
     {
+        // Force EventSource construction at enable-time so listeners can subscribe deterministically.
+        // This avoids CI-only timing races where first telemetry events happen before listener attachment.
         _ = HttpUserAgentParserEventSource.Log;
         Interlocked.Or(ref s_enabledFlags, EventCountersFlag);
     }