BUG: Re-subscribe when internet connection is lost and regained in notion-js

[andrewjaykeller]

Expected

A client should be able to put their process to sleep and wake it up t time later, generally greater than 3 minutes, and be able to immediately resume getting metrics.

Problem

A new subscription is created when Notion is instantiated with this library. Then if the client is, say a developer console in a chrome tab, cut off from the internet for more than two minutes (e.g. 30 minutes during a commute to work) the subscription is automatically cleaned up by the firebase API. Then when the client reconnects to the internet again the subscription is not requested again and no metrics begin to stream into our client.

Solution

Implement a local store in Notion JS to request metrics again on reconnecting to firebase servers.

[alexcastillo]

Fixed on #38