Sudharsan GS

Improve docs for usage of & with filbert.

1

Currently, we don't have proper docs for the usage of `&`(selector) with filbert. There are chances people get confused with `&`(selector) as a parent selector and not as how it...

feat: throw error if local network permissions are not enabled

3

A fix to address #177 Have modified [NsdServiceImpl.java](https://github.com/sudharsangs/react-native-zeroconf/commit/6131483ba16c64d7991f13c2eef696a008934f00#diff-1bc1f5a9e7fe86eeb7abf50bb6dece85f7dbcae4ff6223ac9df27dbfad212697) and [RNZeroconf.m](https://github.com/sudharsangs/react-native-zeroconf/commit/6131483ba16c64d7991f13c2eef696a008934f00#diff-f6134b3598ec57d2409991415d979fd0119454619a9dbca56eb6414c77faf0ff) to throw errors if local network permissions are not given