Fix document on watch

[takassh]

Motivation

tokio::sync::watch should be a single-producer, multi-consumer channel afaik.
Actually, it can't be cloned.
So the current documentation may lead misunderstanding.

Solution

Fixed documentation

[mox692]

Thanks for the PR.

Clone of watch::Sender was introduced in this PR, and that change was shipped in the latest v1.37.0 release.

If you are not using v1.37.0 tokio, then you probably cannot use Sender's Clone.

[takassh]

@mox692
Ah thank you!
then this document may be wrong?
https://tokio.rs/tokio/tutorial/channels#tokios-channel-primitives

which says watch: single-producer, multi-consumer. Many values can be sent, but no history is kept. Receivers only see the most recent value.

Can I fix it?

[mox692]

Thanks, that correction would be helpful.

[takassh]

Thanks for the quick response!
let me close this.