Program.cs

// Cache the delegate
private static Func<MyClass, int, int, int> _cachedDelegate;

static void BuildCache()
{
    MethodInfo method = typeof(MyClass).GetMethod("Calculate");
    _cachedDelegate = (Func<MyClass, int, int, int>)Delegate
        .CreateDelegate(typeof(Func<MyClass, int, int, int>), method);
}

// Invoke (much faster)
int result = _cachedDelegate(instance, 5, 10);