public static void AddRange<T>([NotNull] this ICollection<T> source, [NotNull] T[] items)

S>public static void AddRange<T>([NotNull] this ICollection<T> source, [NotNull] T[] items)
S>

Because methods are the means of taking action, the design guidelines require that method names be verbs or verb phrases. Following this guideline also serves to distinguish method names from property and type names, which are noun or adjective phrases.

// Expression<Func<int, int, int>>
var expression = ExpressionHelpers.Func((int x, int y) => x + y); // Имя условное

        //A simple method that denies reentrancy.
        static bool UseResource()
        {
            //0 indicates that the method is not in use.
            if(0 == Interlocked.Exchange(ref usingResource, 1))
            {
                Console.WriteLine("{0} acquired the lock", Thread.CurrentThread.Name);

                //Code to access a resource that is not thread safe would go here.

                //Simulate some work
                Thread.Sleep(500);

                Console.WriteLine("{0} exiting lock", Thread.CurrentThread.Name);

                //Release the lock
                Interlocked.Exchange(ref usingResource, 0);
                return true;
            }
            else
            {
                Console.WriteLine("   {0} was denied the lock", Thread.CurrentThread.Name);
                return false;
            }
        }
    }

InterlockedOperations.NonReentrant(ref intFlagField, ()=>SomeCode()); // тип флага только int, на всякий уточняю :)