tikv/client-go ? reverse-engineered prompt

Build me a Go client library for TiKV that lets an app talk to a TiKV cluster and store and read key value data easily.

I want it to support both normal transactional usage and raw key value usage, with the kinds of features people expect from TiKV like reads, writes, retries, and basic error handling. It should feel like a real reusable library, not just a demo, so include a few simple examples that show how to connect and do common operations.

Please also add tests, including unit tests and a way to run integration tests against a real TiKV cluster. If there are any current TiKV or TiDB client details I need to follow, look up the latest docs online and make sure the code matches them.