Disable TSO for raw clients?

[ankurmittal]

Hi,

It seems tso is enabled and running in background for raw clients (even though get_timestamp is never called?) and steals works from other tokio tasks due to aggressive self wakes. Can we disable creation of tso background task for raw clients?

[ti-chi-bot]

Welcome @ankurmittal! It looks like this is your first issue to tikv/client-rust 🎉