This CL contains breaking changes for package:dtd and prepares both package:dart_service_protocol_shared and package:dtd for publish.
This CL also fixes https://github.com/dart-lang/sdk/issues/60757 so that DTD-registered services are sent over the `Service` stream upon initial subscription like what is done for client-registered services.
Change-Id: I619af816e64af01864c7ed9b98743c6691bf7e0b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/429161
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Kenzie Davisson <kenzieschmoll@google.com>