Unfortunately, Rust kept nearly the same design for its `std::io::Read` trait. It only separates the two "error" cases from the three "success" cases, so you st

Unfortunately, Rust kept nearly the same design for its `std::io::Read` trait. It only separates the two "error" cases from the three "success" cases, so you still have to check for `ErrorKind::Interrupted` in the error case, and for `Ok(0)` in the success case (and when the passed buffer has zero length, you still can't distinguish between end-of-file and success, though that's not Rust's fault). A better design could have used a return type with more alternatives than just `Ok(n)` or `Err(e)`.