[core] add thread safe random to DI

Core/Startup.cs

@@ -45,6 +45,8 @@ namespace Kruzya.TelegramBot.Core
             services.AddSingleton<UserService>();
             services.AddSingleton<IAntiFlood, MemoryAntiFloodService>();
 
+            services.AddSingleton<ThreadSafeRandom>();
+
             // Trigger module handlers.
             _core.Modules.ConfigureServices(services);
         }

Core/ThreadSafeRandom.cs

@@ -0,0 +1,43 @@
+using System;
+
+namespace Kruzya.TelegramBot.Core;
+
+public class ThreadSafeRandom
+{
+    private static readonly Random Global = new();
+    [ThreadStatic] private static Random _local;
+
+    public int Next()
+    {
+        CheckLocal();
+
+        return _local.Next();
+    }
+
+    public int Next(int minValue, int maxValue)
+    {
+        CheckLocal();
+
+        return _local.Next(minValue, maxValue);
+    }
+
+    public int Next(int maxValue)
+    {
+        CheckLocal();
+
+        return _local.Next(maxValue);
+    }
+
+    private static void CheckLocal()
+    {
+        if (_local == null)
+        {
+            int seed;
+            lock (Global)
+            {
+                seed = Global.Next();
+            }
+            _local = new Random(seed);
+        }
+    }
+}