 
            Sorry to have missed that.
Fwiw I think the lock (and probably a different one, there's no need to lock the fd cache) should be taken again within `cache_inproc_sync` but only for the things where it's actually necessary.
It does rather costly calls, like `mmap` and there's things like `InterlockedCompareExchangePointer` in it which are rather pointless otherwise.
