call publisher start

[xiaoyachong]

I added code to call start() in the publisher. It looks like start() is now being called for the operator and the listener as well.

This could cause a problem because LSEWSResultPublisher connects to the listener within its start() method, see LSE companion PR and arroyoXPS companion.

[dylanmcreynolds]

This is great. I did similar with listeners, but forgot about publishers.

There's a linting error and one failed test. When you fix these we can merge this. Thanks!

[xiaoyachong]

here's a linting error

Thanks. I use black to fix the error. Could we merge it now?