Implement deferred core utility parity APIs/tests and refresh tracking artifacts

dotnet/src/ZB.MOM.NatsNet.Server/Internal/RateCounter.cs

@@ -38,6 +38,12 @@ public sealed class RateCounter
         Interval = TimeSpan.FromSeconds(1);
     }
 
+    /// <summary>
+    /// Factory wrapper for Go parity.
+    /// Mirrors <c>newRateCounter</c>.
+    /// </summary>
+    public static RateCounter NewRateCounter(long limit) => new(limit);
+
     /// <summary>
     /// Returns true if the event is within the rate limit for the current window.
     /// Mirrors <c>rateCounter.allow</c>.