time: time.After uses memory until duration times out

[ston1th]

I would like to see some memory usage information in the docs for time.After like time.Tick already has.

[bradfitz]

See also: #8895 and #8898

But worst case we can just document something.

[dhiltonp]

I just got bit by this; after 10 minutes of execution, my program had 80MB used just by timers.

For now I've switched to NewTimer so I can explicitly stop them.

Looking forward to the fix.