[feature request] Network connectivity checker

[d.healey]

Currently we can use Server.isOnline() to see if there is an internet connection. This works by pinging google's server and seeing if it gets a result. It's a basic solution to the problem but not ideal. For example I've had users in China behind the great firewall who are able to connect to my server but not Google's. I've also had other users who have a slow connection and have to wait quite a while for the check to return, and in the meantime it looks like my plugin's just hanging or frozen.

A better solution is to ask the OS if there is currently an active network connection.

After googling the problem it seems another JUCE user has already come up with a way to do it.

@Christoph-Hart If you think this is good and when you have time, could you implement it, and perhaps add a broadcaster too?

squarepine_core/modules/squarepine_core/networking/NetworkConnectivityChecker.h at main · SquarePine/squarepine_core

Exceptional JUCE/C++ modules that accelerate app and plugin development. - squarepine_core/modules/squarepine_core/networking/NetworkConnectivityChecker.h at main · SquarePine/squarepine_core

GitHub (github.com)

Additionally this also tells us the type of connection the system is using. This is nice because we can give the user the option of only downloading large files when not using mobile data for example.