As of dotnet/corefx#33781, the BitArray class contains unsafe code as a performance optimization. Since BitArray instances are not thread-safe, this opens the possibility that improper cross-thread access to a BitArray instance may result in global memory corruption.

We should modify the BitArray internal logic to be resilient against this possibility. We don't need to make the type thread-safe, but improper cross-thread access shouldn't be able to cause damage beyond corruption of the individual BitArray instances involved.