• Fixes using the (non-default) read_buf feature with Rust nightly newer than nightly-2023-11-01 by opting in to the core_io_borrowed_buf feature and updated BorrowedBuf, BorrowedCursor types.

What's Changed

• Fix build: new feature needed for std::io::BorrowedBuf et al. by @ctz in https://github.com/rustls/rustls/pull/1582
• v0.21.9 preparation by @cpu in https://github.com/rustls/rustls/pull/1592

Full Changelog: https://github.com/rustls/rustls/compare/v/0.21.8...v/0.21.9