Add new sync implementation

Author: simolus3

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

@@ -74,6 +74,32 @@ enum SyncClientImplementation {
   static const defaultClient = dart;
 }
 
+/// The PowerSync SDK offers two different implementations for receiving sync
+/// lines: One handling most logic in Dart, and a newer one offloading that work
+/// to the native PowerSync extension.
+enum SyncClientImplementation {
+  /// A sync implementation that decodes and handles sync lines in Dart.
+  @Deprecated(
+    "Don't use SyncClientImplementation.dart directly, "
+    "use SyncClientImplementation.defaultClient instead.",
+  )
+  dart,
+
+  /// An experimental sync implementation that parses and handles sync lines in
+  /// the native PowerSync core extensions.
+  ///
+  /// This implementation can be more performant than the Dart implementation,
+  /// and supports receiving sync lines in a more efficient format.
+  ///
+  /// Note that this option is currently experimental.
+  @experimental
+  rust;
+
+  /// The default sync client implementation to use.
+  // ignore: deprecated_member_use_from_same_package
+  static const defaultClient = dart;
+}
+
 @internal
 extension type ResolvedSyncOptions(SyncOptions source) {
   factory ResolvedSyncOptions.resolve(