I don't think that's true - you can use the buffer protcol to give one object a view into another but those objects' classes need to be written in C in order to

I don't think that's true - you can use the buffer protcol to give one object a view into another but those objects' classes need to be written in C in order to allow that exchange to happen. But if even if you were able to modify a buffer-protocol buffer directly using native Python, that would keep the GIL locked, which would prevent simultaneous access from multiple threads.