Merge pull request #12 from AntonioFalcao/main

Adding constraint on caching singletons sample code

Author: davidfowl

1.md

@@ -192,13 +192,15 @@ If you need to cache an instance of something based on type, then you can store
 public class Factory
 {
     public T Create<T>()
+        where T : new()
     {
         return Cache<T>.Instance;
     }
 
     private static class Cache<T>
+        where T : new()
     {
-        public static readonly T Instance = new T();
+        public static readonly T Instance = new();
     }
 }
 ```
@@ -209,11 +211,13 @@ You can use the JIT to cache instances on your behalf instead of a slower `Concu
 public class Factory
 {
     public T Create<T>()
+        where T : new()
     {
         return Cache<T>.Instance;
     }
 
     private static class Cache<T>
+        where T : new()
     {
         public static readonly T Instance = CallExpensiveMethodToBuildANewInstance();