Upgrade mio dependency

[faern]

Follow up to tokio-rs/mio#1405. Would probably help greatly with the adoption rate of the fixed versions of net2 and miow. Helps unblock rust-lang/rust#78802. See that PR for more details.

[sfackler]

How would this help with the adoption rate? People would pick this up with a cargo update, but that would pick up the mio bump anyway.

[faern]

Because a lot of people never/seldom do cargo update. They only hand-pick some updates they need or want with cargo update -p <something>. How would you otherwise explain that net2 0.2.33 that came out in 2018 still sees ~2500 downloads a day?

[sfackler]

But if they never cargo update, then they will never pick up this new version of tokio, right?

[sfackler]

Yanking is the mechanism to aggressively pull dependencies forward when necessary.

[faern]

I said/meant they never cargo update without -p. Because it brings in a ton of updates and people don't want shit to break. So they only upgrade the crates they know about or care about. tokio is one of those crates that people very often depend directly on and want the latest. It's a well known project. They will likely hand-pick tokio updates hoping it will bring them features or performance improvements. In this case it will help them not segfault once std is changed :)

[faern]

Yanking is the mechanism to aggressively pull dependencies forward when necessary.

Yes I agree. Having all versions of net2, socket2, miow and mio that are making the invalid memory assumption yanked would be awesome. Let's do it. But yanking won't cause existing projects with a lockfile to upgrade, will it? So I think both solutions are needed/can help.

[faern]

@sfackler Do as you see fit. You are the reviewer of the PR on std so I know you are familiar with the topic. I'm just trying to help force adoption in order to make the change possible faster and the transition smoother.

Maybe you can help get all old versions of net2 and socket2 yanked? I will talk to some people and see if I can do the same to miow that I'm now a maintainer of.

[carllerche]

@faern yanking is not a reliable mechanism and IMO should not be employed at this point for this.