This implements server.listen({ fd: <filedescriptor> }). The fd should
refer to an underlying resource that is already bound and listening, and
causes the new server to also accept connections on it.
Not supported on Windows. Raises ENOTSUP.
Regarding discussion in #3198. Passing the worker as an argument
to an event emitted on the worker is redundant, and an unnecessary
break in consistency vs the events on the ChildProcess objects.
It was removed from 'exit', but 'listening' and others were
overlooked. This corrects that oversight.
test: fixes due to new cluster api.
- changed worker `death` to `exit`.
- corrected argument type expected by worker `exit` handler.
test: more tests of cluster.worker death
cluster: fixed arguments on worker 'exit' event
worker 'exit' event now emits arguments consistent with the
corresponding event in child_process module.
This patch add a worker.disconnect() method there will stop the worker from accepting
new connections and then stop the IPC. This allow the worker to die graceful.
When the IPC has been disconnected a 'disconnect' event will emit.
The patch also add a cluster.disconnect() method, this will call worker.disconnect() on
all connected workers. When the workers are disconneted it will then close all server
handlers. This allow the cluster itself to self terminate in a graceful way.