Move multi-threaded execution to multi-process architecture

Signed-off-by: Imran M Yousuf <imyousuf@newscred.com>
Make sure that stat is returned even if its null

Also add documentation for the APIs so that we can have more impls for
them and expand what we can do.

Signed-off-by: Imran M Yousuf <imyousuf@newscred.com>