Added AsyncReadWriteLock

Source/MQTTnet.Benchmarks/AsyncReadWriteLockBenchmark.cs

@@ -0,0 +1,40 @@
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Jobs;
+using MQTTnet.Internal;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace MQTTnet.Benchmarks
+{
+    [SimpleJob(RuntimeMoniker.Net60)]
+    [SimpleJob(RuntimeMoniker.Net70)]
+    [MemoryDiagnoser]
+    public class AsyncReadWriteLockBenchmark : BaseBenchmark
+    {
+
+        [Benchmark]
+        public async Task Synchronize_100_Read_Tasks()
+        {
+            const int tasksCount = 100;
+            var tasks = new Task[tasksCount];
+            var asyncReadWriteLock = new AsyncReadWriteLock();
+
+            for (var i = 0; i < tasksCount; i++)
+            {
+                tasks[i] = Task.Run(async () =>
+                {
+                    using (await asyncReadWriteLock.EnterReadAsync().ConfigureAwait(false))
+                    {
+                        await Task.Delay(5).ConfigureAwait(false);
+                    }
+                });
+            }
+
+            await Task.WhenAll(tasks).ConfigureAwait(false);
+        }
+
+    }
+}