No, that's not the best description. The Io interface is actually one of the best cancellation stories out there. If you combine it with defer/errdefer, you get safer cancellation guarantees than you have in async Rust (you can do async "drop" for example). The only problematic part is the interaction between the Reader/Writer interface and the Io interface, with regards to error handling.

> The only problematic part is the interaction between the Reader/Writer interface and the Io interface, with regards to error handling.

The fact that error handling suffers when combining two of the base interfaces of the standard library is pretty rough though? I don't think rust has that particular problem.