Keep track of open xhrs and only flush if there aren't too many

[msaspence]

To help prevent barometer's requests holding up the application's requests we could keep track of open xhrs and only send the buffer if less than a specified number are open.

[theninj4]

Currently we wait at least 5 seconds between flushing the buffer and timeout each XHR request after 4 seconds. It shouldn't be possible to ever have more than one request in-flight at once.

[msaspence]

I mean keep track of other requests so we don't complete with the application for what might be limited band width.

[theninj4]

Ahh interesting. Great idea 👍