Need background event listener on notification receive (Push.addListener('startup') called only when app is reopen)

Hi,

I need to listen notification receive event regardless of app is open,closed or is in background. I tried **Push.addListener('startup')** but it gets called when app is re-open from background state.

Actually i want to do some processing whenever there is new notification is received if app is open,closed or in background

Start by tracing how Push.addListener('startup') is handled and how notification receipt is exposed for the app states named in the issue. Clarify the supported platforms and define done as processing a newly received notification while the app is open, closed, or in the background.

Written by the indexing model from the issue text.