C# way of doing ObjC blocks.

gistfile1.cs

/* Declaration */

// In ObjC
typedef void (^onCompletion)(bool completed);

// In C#
public delegate void OnCompletion(bool completed);

/* Implementation */

// In ObjC
- (void)myAsyncMethod:(onCompletion)completion
{
  // blablabla...
  completion(YES);
}

// In C#
public void MyAsyncMethod(OnCompletion completion)
{
  // blablabla...
  completion(true);
}

/* Usage */

// ObjC
[obj myAsyncMethod:^(completed) {
  // finish !
}];

// C#
obj.MyAsyncMethod((completed) => {
  // finish !
});