34b4c914a4
Adds a DDS RPC which allows for stream history to be manually requested in addition to being sent upon initial stream subscription. Also adds an initial implementation of package:dds/vm_service_extensions.dart, which adds DDS functionality to the `VmService` class. Fixes https://github.com/dart-lang/sdk/issues/44505 Change-Id: I198a6fd7fca15f131a6fdd95e7860a6f98ef06a7 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/177182 Reviewed-by: Kenzie Schmoll <kenzieschmoll@google.com> Commit-Queue: Ben Konyi <bkonyi@google.com>