Misc API improvements

Author: simolus3

packages/powersync_core/lib/src/sync/connection_manager.dart

@@ -372,7 +372,7 @@ final class _SyncStreamSubscriptionHandle implements SyncStreamSubscription {
   Map<String, Object?>? get parameters => _source.parameters;
 
   @override
-  Future<void> unsubscribe() async {
+  void unsubscribe() async {
     _finalizer.detach(this);
     _source.decrementRefCount();
   }

packages/powersync_core/lib/src/sync/stream.dart

@@ -77,12 +77,12 @@ abstract interface class SyncStreamSubscription
   /// this stream subscription.
   Future<void> waitForFirstSync();
 
-  /// Removes this stream subscription from the database, if it has been
-  /// subscribed to explicitly.
+  /// Removes this subscription.
   ///
-  /// The subscription may still be included for a while, until the client
-  /// reconnects and receives new snapshots from the sync service.
-  Future<void> unsubscribe();
+  /// Once all [SyncStreamSubscription]s for a [SyncStream] have been
+  /// unsubscribed, the `ttl` for that stream starts running. When it expires
+  /// without subscribing again, the stream will be evicted.
+  void unsubscribe();
 }
 
 /// An `ActiveStreamSubscription` as part of the sync status in Rust.

packages/powersync_core/lib/src/sync/sync_status.dart

@@ -2,7 +2,6 @@ import 'dart:math';
 
 import 'package:collection/collection.dart';
 import 'package:meta/meta.dart';
-import '../database/powersync_database.dart';
 
 import 'bucket_storage.dart';
 import 'protocol.dart';
@@ -120,10 +119,8 @@ final class SyncStatus {
 
   /// All sync streams currently being tracked in this subscription.
   ///
-  /// This returns null when the sync stream is currently being opened and we
-  /// don't have reliable information about all included streams yet (in that
-  /// state, [PowerSyncDatabase.subscribedStreams] can still be used to
-  /// resolve known subscriptions locally).
+  /// This returns null when the database is currently being opened and we
+  /// don't have reliable information about all included streams yet.
   Iterable<SyncStreamStatus>? get activeSubscriptions {
     return _internalSubscriptions?.map((subscription) {
       return SyncStreamStatus._(subscription, downloadProgress);
@@ -221,7 +218,6 @@ final class SyncStreamStatus {
 
   SyncSubscriptionDescription get subscription => _internal;
   StreamPriority get priority => _internal.priority;
-  bool get isDefault => _internal.isDefault;
 
   SyncStreamStatus._(this._internal, SyncDownloadProgress? progress)
       : progress = progress?._internal._forStream(_internal);

packages/powersync_core/test/sync/stream_test.dart

@@ -175,8 +175,8 @@ void main() {
               subscription: isSyncSubscription(
                 name: 'default_stream',
                 parameters: null,
+                isDefault: true,
               ),
-              isDefault: true,
             ),
           ],
         ),
@@ -207,7 +207,7 @@ void main() {
 
     // Given that the subscription has a TTL, dropping the handle should not
     // re-subscribe.
-    await subscription.unsubscribe();
+    subscription.unsubscribe();
     await pumpEventQueue();
     expect(syncService.controller.hasListener, isTrue);
   });

packages/powersync_core/test/sync/utils.dart

@@ -58,27 +58,30 @@ TypeMatcher<ProgressWithOperations> progress(int completed, int total) {
 TypeMatcher<SyncStreamStatus> isStreamStatus({
   required Object? subscription,
   Object? progress,
-  Object? isDefault,
 }) {
   var matcher = isA<SyncStreamStatus>()
       .having((e) => e.subscription, 'subscription', subscription);
   if (progress case final progress?) {
     matcher = matcher.having((e) => e.progress, 'progress', progress);
   }
-  if (isDefault case final isDefault?) {
-    matcher = matcher.having((e) => e.isDefault, 'isDefault', isDefault);
-  }
 
   return matcher;
 }
 
 TypeMatcher<SyncSubscriptionDescription> isSyncSubscription({
   required Object name,
   required Object? parameters,
+  bool? isDefault,
 }) {
-  return isA<SyncSubscriptionDescription>()
+  var matcher = isA<SyncSubscriptionDescription>()
       .having((e) => e.name, 'name', name)
       .having((e) => e.parameters, 'parameters', parameters);
+
+  if (isDefault != null) {
+    matcher = matcher.having((e) => e.isDefault, 'isDefault', isDefault);
+  }
+
+  return matcher;
 }
 
 BucketChecksum checksum(