Excluding metrics items from code coverage.

Author: tillig

src/Autofac/Diagnostics/AutofacMetrics.cs

@@ -9,6 +9,7 @@ namespace Autofac.Diagnostics;
 /// <summary>
 /// Centralized metrics wiring for Autofac diagnostics.
 /// </summary>
+[ExcludeFromCodeCoverage]
 internal static class AutofacMetrics
 {
     private const string DiagnosticsEnvironmentVariable = "AUTOFAC_METRICS";

src/Autofac/Diagnostics/ValueStopwatch.cs

@@ -11,6 +11,7 @@ namespace Autofac.Diagnostics;
 /// <summary>
 /// Lightweight stopwatch for timing without heap allocations.
 /// </summary>
+[ExcludeFromCodeCoverage]
 internal struct ValueStopwatch
 {
 #if !NET7_0_OR_GREATER