Is pykdtree free-threading compatible?

[djhoese]

Python 3.13 has a free-threading mode that is disabled by default. See this guide for migrating extensions to be compatible:

https://py-free-threading.github.io/porting

My question is, is pykdtree compatible with free-threading? It does a lot of openmp and nogil stuff for the majority of its work and everything revolves around the idea of a KDTree object so I don't see why it couldn't be. I mean, if two separate threads called .query at the same time that should be fine as this method initializes all structures it uses and returns a single result. There is no caching or global state involved.

@storpipfugl Any concerns that you can think of as the original creator of this code?