shutdown method on master doesn't do the shutdown

[nulltier]

Here

luster/lib/master.js

Line 421 in f2811a1

this.emit('shutdown');

shutdown method emits the "shutdown" event.

_onSignalQuit knows about the issue and attaching one-time listener for itself

luster/lib/master.js

Line 62 in f2811a1

.once('shutdown', () => process.exit(0))

Without proper on shutdown listener users have no ability to stop luster from their code, only the system signals 'SIGINT' and 'SIGQUIT' can do the job.