Refactor SimilarityIndex initialization sync and setupDimension method public

[buhe]

Hi, @ZachNagengast
Constructor as async is not very convenient most of the time

BR
buhe

[ZachNagengast]

I definitely see your point that async is sometimes hard to work with - it would help all the existing code though if this was a secondary convenience init method, rather than a direct change to the default. That may require the use of semaphores to work properly.

Another approach you might want to consider is an entirely new class that is a subclass of the SimilarityIndex but has a non-async init, a good reference for how to handle both is the swift-argument-parser project: apple/swift-argument-parser#404

The code looks good otherwise, thanks for adding the documentation line.

[buhe]

Okey, i will see apple/swift-argument-parser#404