Not unique Package.ID generation.

[KotM]

It seems like both IQ and Message classes (inherited from Package) incorrectly generates ID values when interacting with multiple threads. Sometimes these classes may produce the ID was generated before.

Tested on latest Jabber-net version too.

Please find below simply UnitTest with reproduction this issue almost constantly.

        [TestMethod]
        public void MultipleIQCreation()
        {
            ConcurrentBag<string> ids = new ConcurrentBag<string>();

            var doc = new XmlDocument();

            //for (int i = 0; i < 500; i++)
            //{
            //    ids.Add((new IQ(doc)).ID);
            //}

            Parallel.For(0, 500, i => ids.Add((new IQ(doc)).ID));

            Assert.AreEqual(500, ids.Count);
            Assert.AreEqual(500, ids.Distinct().Count());
        }

[KotM]

Workaround it simply -- I've just assigned my own id to the packet. But it would be great to fix it on Jabber-net side. Suppose, the fix would be easy enough, something like Interlocked.Increment(ref _jabberPacketId).

[ForNeVeR]

Ah my gosh, this library is full of threading problems. Thanks for your wonderful unit test, I'll take a look.

[pomoika]

The bug is in JabberNet/jabber/protocol/Element.cs, method NextID. It should be changed as follows:

public static string NextID()
{
    return "JN_" + System.Threading.Interlocked.Increment(ref s_counter).ToString();
}

[ForNeVeR]

Thanks for your help, it definitely was an issue highlighted by @pomoika. It's fixed now and I've published a new preview release 3.0.0-preview3.