identifies the asynchronous job so the JobExecutor
can differ between more then ones.
Parameter Result
should be the same like for the synchronous mode on XJob::execute().
It provides information about success or failure of job execution. It's possible too,
to use special protocol (which depends from real implementation) between
JobExecutor and a real job. So it can be possible to:
deregister the job
let him registered although execution was successfully(!)
make some job specific data persistent inside the job configuration which
is provided by the executor.