not thread safe, is crashing in the Dictionary.Add

[rromerik]

Mvp.Xml.NetStandard/library/Mvp.Xml/Common/XPath/XPathCache.cs

Line 32 in ffaa727

Cache[expression] = expr;

I had some crash in this file, when I load two file in parallel, betting a null ptr exception in the dictionary.add every variables are valid, I guess the dictionary is resizing while we are adding.

not sure if ThreadStaticAttribute or ConcurrentDictionary will be the best fix for this!

[SpocWeb]

ConcurrentDictionary would be the way to go, but it blocks. With ThreadStaticAttribute you create a separate Dictionary in each Thread which is Overhead and probably not what you want

[rromerik]

an other option will be to lets the user change/set the default cache dictionary if we want to!