Could we choose the cancel exception when calling `Mutex.cancel()`

[krassowski]

This is a proposal for a slight expansion of the API by allowing to configure the error thrown not only in the constructor but also as an argument to cancel(). This would allow the exception handler to enter different branches depending on what logic cancelled the mutex, which I find highly valuable.

What do you think?

[DirtyHairy]

Hi @krassowski !

That's a good suggestion. I'll see to include this in the next release.