Update README.md

tk-codes · web-flow · commit de97c30d1e34 · 2016-12-21T22:45:23.000+01:00
diff --git a/CreationalPatterns/Singleton/README.md b/CreationalPatterns/Singleton/README.md
@@ -4,11 +4,14 @@
 
 ## Static Initialization
 
-:thumbsup: **You may want to create your Singleton eagerly, if**
+:thumbsup: **You may want to create your Singleton eagerly**, if
 * your application always creates and uses an instance of the `Singleton`
 * the overhead of creation and runtime aspects of the Singleton are not onerous
 
-[ChocolateBoiler_StaticInit.cs](CreationalPatterns/Singleton/ChocolateBoiler_StaticInit.cs).
+:thumbsdown: **Downside**
+* You have less control over the mechanics of the instantiation
+
+[ChocolateBoiler_StaticInit.cs](/CreationalPatterns/Singleton/ChocolateBoiler_StaticInit.cs).
 ```cs
     public sealed class ChocolateBoiler_StaticInit
     {
@@ -29,8 +32,11 @@ The class is marked as **sealed** to prevent derivation, which could add instanc
 
 Because the **Singleton** instance is referenced by a private static member variable, the instantiation does not occur until the class is first referenced by a call to the **Instance** property. This solution therefore implements a form of the lazy instantiation property, as in the Design Patterns form of Singleton.
 
-:thumbsdown: **Downside**
-* You have less control over the mechanics of the instantiation
+## Multithreaded Singleton
+
+:thumbsup: **Use double-checked locking**, if
+* you want to keep separate threads from creating new instances of the singleton at the same time (thread-safe)
+* you want to create an instance only when the instance is needed.
 
 Reference: 
 * MSDN - [Implementing Singleton in C#](https://msdn.microsoft.com/en-us/library/ff650316.aspx)
