154e885bd4
Fixes situation where confusing errors were thrown when DDS was shut down while starting up (e.g., StateError from in-flight requests, WebSocket exceptions due to the VM service disappearing, etc). Change-Id: I8293eaf4a176d9258fc2c794d595dc926711f31a Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/164601 Reviewed-by: Ryan Macnak <rmacnak@google.com> Commit-Queue: Ben Konyi <bkonyi@google.com>