GHSA-4Q83-7CQ4-P6WG `tokio::io::ReadHalf<T>::unsplit` is Unsound

tokio::io::ReadHalf::unsplit can violate the Pin contract The soundness issue is described in the tokio/issues5372 Specific set of conditions needed to trigger an issue a !Unpin type in ReadHalf is unusual, combined with the difficulty of making any arbitrary use-after-free exploitable in Rust...