Sometimes the implementation can expose drawbacks of initial design. I don't know whether there was good reason for omitting the support of the buffer protocol (in that case the PEP should be updated) or this is just an oversign. We should ask Ethan about this.

The change proposed by Xiang looks correct, but not very efficient. It makes one redundant copy of the data. More efficient implementation will complicate the code, and that can hit the performance of other cases.