Fix benchmark client incorrectly measuring warmup RPS (#1007)

Author: JamesNK

perf/benchmarkapps/GrpcAspNetCoreServer/Program.cs

@@ -110,7 +110,14 @@ public static IHostBuilder CreateHostBuilder(string[] args)
                     if (Enum.TryParse<LogLevel>(config["LogLevel"], out var logLevel) && logLevel != LogLevel.None)
                     {
                         Console.WriteLine($"Console Logging enabled with level '{logLevel}'");
-                        loggerFactory.AddConsole(o => o.TimestampFormat = "ss.ffff ").SetMinimumLevel(logLevel);
+
+                        loggerFactory
+#if NETCOREAPP3_1
+                            .AddConsole(o => o.TimestampFormat = "ss.ffff ")
+#else
+                            .AddSimpleConsole(o => o.TimestampFormat = "ss.ffff ")
+#endif
+                            .SetMinimumLevel(logLevel);
                     }
                 })
                 .UseDefaultServiceProvider((context, options) =>

perf/benchmarkapps/GrpcClient/Program.cs

@@ -48,8 +48,8 @@ class Program
         private static List<List<double>> _latencyPerConnection = null!;
         private static double _maxLatency;
         private static Stopwatch _workTimer = new Stopwatch();
-        private static bool _warmingUp;
-        private static bool _stopped;
+        private static volatile bool _warmingUp;
+        private static volatile bool _stopped;
         private static SemaphoreSlim _lock = new SemaphoreSlim(1);
         private static List<(double sum, int count)> _latencyAverage = null!;
         private static int _totalRequests;
@@ -112,6 +112,7 @@ private static async Task StartScenario()
             var cts = new CancellationTokenSource();
             cts.CancelAfter(TimeSpan.FromSeconds(_options.Duration + _options.Warmup));
 
+            _warmingUp = true;
             _ = Task.Run(async () =>
             {
                 await Task.Delay(TimeSpan.FromSeconds(_options.Warmup));