Track LocalMods as part of monolith

LocalMods/More Level Content/CSharp/Shared/Utils/Singleton.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Barotrauma.MoreLevelContent.Shared.Utils
+{
+    public abstract class Singleton<T> where T : class
+    {
+        /// <summary>
+        /// Static instance. Needs to use lambda expression
+        /// to construct an instance (since constructor is private).
+        /// </summary>
+        private static readonly Lazy<T> sInstance = new Lazy<T>(() => CreateInstanceOfT());
+
+        /// <summary>
+        /// Gets the instance of this singleton.
+        /// </summary>
+        public static T Instance => sInstance.Value;
+
+        /// <summary>
+        /// Creates an instance of T via reflection since T's constructor is expected to be private.
+        /// </summary>
+        /// <returns></returns>
+        private static T CreateInstanceOfT() => Activator.CreateInstance(typeof(T), true) as T;
+
+        public abstract void Setup();
+    }
+}