Tor bootstrap hangs when offline

Hi Nick. When launching a tor process stem uses bootstrap messages to determine when the instance we launch is available. Recently-ish tor changed such that when offline tor bootstrapping does not progress past 0%, printing hundreds of...

Jan 29 11:36:27.000 [warn] Problem bootstrapping. Stuck at 0% (starting): Starting. (Network is unreachable; NOROUTE; count 11; recommendation warn; host 322C6E3A973BC10FC36DE3037AD27BC89F14723B at 212.83.154.33:8443)
Jan 29 11:36:28.000 [warn] Problem bootstrapping. Stuck at 0% (starting): Starting. (Network is unreachable; NOROUTE; count 12; recommendation warn; host F741E5124CB12700DA946B78C9B2DD175D6CD2A1 at 163.172.154.162:9001)
Jan 29 11:36:28.000 [warn] Problem bootstrapping. Stuck at 0% (starting): Starting. (Network is unreachable; NOROUTE; count 14; recommendation warn; host D71B1CA1C9DC7E8CA64158E106AD770A21160FEE at 185.34.33.2:31415)
Jan 29 11:36:29.000 [warn] Problem bootstrapping. Stuck at 0% (starting): Starting. (Network is unreachable; NOROUTE; count 13; recommendation warn; host F2DFE5FA1E4CF54F8E761A6D304B9B4EC69BDAE8 at 129.13.131.140:443)
Jan 29 11:36:30.000 [warn] Problem bootstrapping. Stuck at 0% (starting): Starting. (Network is unreachable; NOROUTE; count 14; recommendation warn; host 47C42E2094EE482E7C9B586B10BABFB67557030B at 185.220.101.34:20034)
Jan 29 11:36:30.000 [warn] Problem bootstrapping. Stuck at 0% (starting): Starting. (Network is unreachable; NOROUTE; count 14; recommendation warn; host B06F093A3D4DFAD3E923F4F28A74901BD4F74EB1 at 178.17.174.14:9001)
Jan 29 11:36:31.000 [warn] Problem bootstrapping. Stuck at 0% (starting): Starting. (Network is unreachable; NOROUTE; count 15; recommendation warn; host CF6D0AAFB385BE71B8E111FC5CFF4B47923733BC at 154.35.175.225:443)

There's a few issues with this...

1. Poor experience from a user perspective. Deluging the user with hundreds of warnings is pretty unhelpful.

2. Stem's ability to launch tor processes no longer works when offline.

3. Stem's integ tests no longer pass when offline. I can sidestep this but first I'd like to confirm if this is the desired behavior from tor or not.