Occasionally a job may be run when the app is in a network-restricted
mode, like a form of doze. When this happens, jobs can timeout due to
lack of network access, causing a cascade of job delays. This is
particularly bad in the case of message retrieval.
To prevent this, if a job that normally requires network detects that no
network is available when running, then we start a foreground
notification.
We have to make some changes, and it's gotten to the point where
maintaining it as a separate library is more hassle than it's worth,
especially with Google releasing WorkManager as the preferred job
scheduling library.
