[plt-scheme] PLT Webserver - (manager-instance-unlock! manager) instance-id

Hi There,

Does anyone know under what circumstances an instance-id of a servlet
gets unlocked, so that the manager can cleanup the instance?

I'm currently cleaning up locked instances with 0 continuations,
but that has a pitfall when a servlet has created a thread, because
the thread will be killed.

Is there any way around that, or should I just avoid starting threads
in servlets?

Thanks in advance for your answers,

--Hans