Multiple attach should be supported

[apostasie]

Description

In terminal 1:

nerdctl run --rm -ti --detach-keys=ctrl-a,ctrl-b --name what debian

Do not detach

Then in terminal 2:

nerdctl attach what

Start typing in terminal 2.

Notice that some characters are displayed on terminal 1, others on terminal 2.

Do the same with docker: it works.

There is something broken either in nerdctl, or maybe in containerd/console.

Steps to reproduce the issue

No response

Describe the results you received and expected

na

What version of nerdctl are you using?

main

Are you using a variant of nerdctl? (e.g., Rancher Desktop)

None

Host information

No response

[apostasie]

Note this was actually explicitly mentioned as a limitation in the original PR introducing attach: #2108

[apostasie]

@AkihiroSuda + feature