Carl Lerche 9d58b70151
sync: move CancellationToken to tokio-util (#2721)
* sync: move CancellationToken to tokio-util

The `CancellationToken` utility is only available with the
`tokio_unstable` flag. This was done as the API is not final, but it
adds friction for users.

This patch moves `CancellationToken` to tokio-util where it is generally
available. The tokio-util crate does not have any constraints on
breaking change releases.

* fix clippy

* clippy again
2020-08-23 17:45:52 +02:00
..