Summary:
Previously we tried continue on network down and it showed good
improvement. But there was a problem: it hurts UX for airplane mode users, it
didn't return error back to user immediately but after 30/60 seconds timeout.
This adds a timer for this feature and it only allows the transport to ignore
network unreachable error for 200ms. After 200ms, it throws and reports to user
if the error persists.
Reviewed By: siyengar
Differential Revision: D15089442
fbshipit-source-id: dd87f4f579187c4b45244a7ee0477d2a0cf1b5d7