When the client opts in to `workspace/tests/refresh` or
`workspace/playgrounds/refresh` via experimental client capabilities,
SourceKit-LSP now maintains a proactive cache of the current test and
playground lists and sends the corresponding `workspace/.../refresh`
notification whenever the cache changes. `workspaceTests()` /
`workspacePlaygrounds()` then serve subsequent fetch requests directly
from the cache.
Add `EntryPointManager`: runs background scans, stores the results,
fires callbacks on changes:
- Start scanning when build targets are updated including initial
updates, any watched files are changed, and index is updated.
- Send '/refresh' server initiated requests when the cache has changed.
- Coalesces rapid invalidations by cancelling any in-flight refresh task.
Also:
- Simplify `SourceKitIndexDelegate` from an `actor` with `AtomicInt32`
to a plain `class`, since it is only called from IndexStoreDB's
internal serial dispatch queue.
Rintaro Ishizaki