CancellationFlags will be used to prevent crashes during the shutdown of Nearby Connections from pending tasks taking too long during the shutdown period. WebRTC using 3 x 10s retries to connect, which means we are potentially waiting for 30 seconds of retries to execute during shutdown (which is longer than the 10s duration alloted for Core shutdown).
By using CancellationFlags, we can prevent the retries occuring during the Shutdown by short-circuiting an in flight AttemptToConnect, and checking for Cancellation before retries.
PiperOrigin-RevId: 539690403
During the destruction of NearbyConnections, Core (which owns ClientProxy) is destructed before ServiceController (which owns EndpointManager), which means any pending tasks on the EndpointManager executor that use ClientProxy will be using
garbage memory. To fix this issue, EndpointManager::DiscardEndpoint will check
for an `is_shutdown` boolean set during ~EndpointManager before accessing
ClientProxy. The assumption is that any accessing of ClientProxy after the
destruction will be invalid.
PiperOrigin-RevId: 532581122
Guogang Li