Add NoProfile about profile

[gbbr]

This sounds good to me considering that:

• @josharian is still open to send a PR, and
• @davecheney is ok with it

[gbbr]

Some thoughts I have on this are:

• Calling it NoProfile would create some stutter in the external context, where you would use it as profile.NoProfile. Personally I would prefer something like profile.Off if this is something that we really need.

• Would you be able to provide a more thorough example of how you would use this? As far as I can see it, the current implementation already allows you to conditionally run profiles via flags or other means. I think adding this additional code might unnecessarily complicate an otherwise simple package, unless I'm missing the point. You can simply do something like:

var p interface {
    Stop()
}
if condition {
    p = profile.Start(/* your options */)
}

// ... 

if p != nil {
    p.Stop()
}

Am I misunderstanding something or is this the same use case?

[marco-m]

Hello, is this issue still valid ?