Merge pull request #535 from Olwaro/loan_pattern

[csharp/en] Adds example of 'using' statement for resources handling

csharp.html.markdown

@@ -30,6 +30,7 @@ using System.Linq;
 using System.Linq.Expressions;
 using System.Net;
 using System.Threading.Tasks;
+using System.IO;
 
 // defines scope to organize code into "packages"
 namespace Learning
@@ -434,6 +435,17 @@ on a new line! ""Wow!"", the masses cried";
             Func<int, int> square = (x) => x * x; // Last T item is the return value
             Console.WriteLine(square(3)); // 9
 
+            // DISPOSABLE RESSOURCES MANAGEMENT - let you handle unmanaged resources easily.
+            // Most of objects that access unmanaged resources (file handle, device contexts, etc.)
+            // implement the IDisposable interface. The using statement takes care of 
+            // cleaning those IDisposable objects for you.
+            using (StreamWriter writer = new StreamWriter("log.txt"))
+            {
+                writer.WriteLine("Nothing suspicious here");
+                // At the end of scope, resources will be released.
+                // Even if an exception is thrown.
+            } 
+
             // PARALLEL FRAMEWORK
             // http://blogs.msdn.com/b/csharpfaq/archive/2010/06/01/parallel-programming-in-net-framework-4-getting-started.aspx
             var websites = new string[] {