Tim was debugging one of those multithreading bugs, where there appeared to be a race condition of some kind. The developer who had initially written the code denied that such a thing could exist: “It’s impossible, I used locks to synchronize the threads!”

Well, he did use locks at the very least.

/// <summary>
/// Performs the synchronisation
/// </summary>
/// <param name="state">Current state</param>
private void Synchronize(object state)
    // Take care that this can only run in one thread at a time
    var lockThis = new Object();
    lock (lockThis)

There is of course, one problem. The object you use for the lock needs to be shared across threads. This is less a “lock” in the sense of an “air lock” and more a lock in the sense of a “complete hull breach”.

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