[supervisor] non blocking terminal reading

[akosyakov]

Right now one client can block reading from a task terminal. Instead we could look into non blocking solutions.

In Theia, we don't directly write to each client but into the ring buffer from this each client then reads with own speed without blocking other clients.

@csweichel pointed out how go channels can be used as ring buffers: https://tanzu.vmware.com/content/blog/a-channel-based-ring-buffer-in-go

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[akosyakov]

@csweichel was prototyping such approach here: 84ca5fe