[Perf] Add helper classes for random values (#24303)

Author: mikeharder

common/Perf/Azure.Test.Perf/RandomByteArray.cs

@@ -0,0 +1,15 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+namespace Azure.Test.Perf
+{
+    public static class RandomByteArray
+    {
+        public static byte[] Create(int size)
+        {
+            var bytes = new byte[size];
+            ThreadsafeRandom.NextBytes(bytes);
+            return bytes;
+        }
+    }
+}

common/Perf/Azure.Test.Perf/RandomStream.cs

@@ -11,7 +11,7 @@ public static class RandomStream
         private static readonly Lazy<byte[]> _randomBytes = new Lazy<byte[]>(() =>
         {
             var randomData = new byte[1024 * 1024];
-            (new Random(0)).NextBytes(randomData);
+            ThreadsafeRandom.NextBytes(randomData);
             return randomData;
         });
 

common/Perf/Azure.Test.Perf/RandomString.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+namespace Azure.Test.Perf
+{
+    public static class RandomString
+    {
+        private const string _alphanumeric = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+        public static string CreateAlphanumeric(int length)
+        {
+            var buffer = new char[length];
+            for (var i = 0; i < length; i++)
+            {
+                buffer[i] = _alphanumeric[ThreadsafeRandom.Next(_alphanumeric.Length)];
+            }
+            return new string(buffer);
+        }
+    }
+}

common/Perf/Azure.Test.Perf/ThreadsafeRandom.cs

@@ -0,0 +1,34 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.Threading;
+
+namespace Azure.Test.Perf
+{
+    // Adapted from https://devblogs.microsoft.com/pfxteam/getting-random-numbers-in-a-thread-safe-way/
+    public static class ThreadsafeRandom
+    {
+        private static readonly Random _globalRandom = new Random();
+
+        private static readonly ThreadLocal<Random> _threadRandom = new ThreadLocal<Random>(() =>
+        {
+            lock (_globalRandom)
+            {
+                return new Random(_globalRandom.Next());
+            }
+        });
+
+        private static Random ThreadRandom => _threadRandom.Value;
+
+        public static int Next() => ThreadRandom.Next();
+
+        public static int Next(int minValue, int maxValue) => ThreadRandom.Next(minValue, maxValue);
+
+        public static int Next(int maxValue) => ThreadRandom.Next(maxValue);
+
+        public static void NextBytes(byte[] buffer) => ThreadRandom.NextBytes(buffer);
+
+        public static double NextDouble() => ThreadRandom.NextDouble();
+    }
+}