v22.1.0

What's new

• @fulara added a way to control TCP_USER_TIMEOUT for a connection using the new tcp_user_timeout option (see #307). Please note that this is only for target_os = "linux".
• @fulara implemented AsRawFd for Conn (see #307)

Fixes

• 3c4d4ee fixes the infinite loop in QueryResult, that may be triggered by a connectivity error (reported by @fulara in #306)

Other

• Conn::drop behavior is now mentioned in the docs (see #308)
• There is now a test that asserts that TiDB connections are properly reused (see #309)