System.Tests.StringTests.Concat_String_ConcurrencySafe C# (CSharp) Method

        public static void Concat_String_ConcurrencySafe()
        {
            var inputs = new string[2] { "abc", "def" };
            var cts = new CancellationTokenSource();
            using (var b = new Barrier(2))
            {
                // String.Concat(string[]) has a slow path that handles the case where the
                // input array is mutated concurrently.  Queue two tasks, one that repeatedly
                // does concats and the other that mutates the array concurrently.  This isn't
                // guaranteed to trigger the special case, but it typically does.
                Task.WaitAll(
                    Task.Run(() =>
                    {
                        b.SignalAndWait();
                        while (!cts.IsCancellationRequested)
                        {
                            string result = string.Concat(inputs);
                            Assert.True(result == "abcdef" || result == "abc" || result == "def" || result == "", $"result == {result}");
                        }
                    }),
                    Task.Run(() =>
                    {
                        b.SignalAndWait();
                        try
                        {
                            for (int iter = 0; iter < 100000000; iter++)
                            {
                                Volatile.Write(ref inputs[0], null);
                                Volatile.Write(ref inputs[1], null);
                                Volatile.Write(ref inputs[0], "abc");
                                Volatile.Write(ref inputs[1], "def");
                            }
                        }

                        finally
                        {
                            cts.Cancel();
                        }
                    }));
            }
        }