"there is always a thread"

[Kevin Buettner]

On Oct 9, 10:27am, Andrew Cagney wrote:

> I'm intending simplifying this so that the code can assume that there's 
> always a "thread".

It depends upon the stratum.  dummy_stratum and file_stratum (and
download_stratum?) will have no thread because nothing's running yet.

> A non-threaded app having a single thread 
> corresponding to the main process.

For the other strata, this should be (made to be) true.

A fallout from this change may be that the process_stratum and
thread_stratum can be merged.

Kevin