adds a/sync options for classify method

packages/mediapipe-task-text/lib/src/tasks/text_classification/text_classifier.dart

@@ -6,11 +6,24 @@ export 'universal_text_classifier.dart'
 
 /// Channel to analyze text via MediaPipe's text classification task.
 abstract class BaseTextClassifier {
+  /// Generative constructor.
   BaseTextClassifier({required this.options});
 
-  /// Configuration object for tasks completed by this classifier.
+  /// Configuration wobject for tasks completed by this classifier.
   final TextClassifierOptions options;
 
-  /// Sends a `String` value to MediaPipe for classification.
-  TextClassifierResult classify(String text);
+  /// Sends a `String` value to MediaPipe for classification. Uses an Isolate
+  /// on mobile and desktop, and a web worker on web, to add concurrency and avoid
+  /// blocking the UI thread while this task completes.
+  ///
+  /// See also:
+  ///  * [classify_sync] for a synchronous alternative
+  Future<TextClassifierResult> classify(String text);
+
+  /// Sends a `String` value to MediaPipe for classification. Blocks the main
+  /// event loop for the duration of the task, so use this with caution.
+  ///
+  /// See also:
+  ///  * [classify] for a concurrent alternative
+  TextClassifierResult classifySync(String text);
 }

packages/mediapipe-task-text/lib/src/tasks/text_classification/text_classifier_io.dart

@@ -1,5 +1,6 @@
 import 'dart:ffi';
 import 'package:ffi/ffi.dart';
+import 'package:flutter/foundation.dart';
 import 'package:logging/logging.dart';
 import 'package:mediapipe_core/mediapipe_core.dart';
 
@@ -11,10 +12,26 @@ final _log = Logger('TextClassifier');
 
 /// TextClassifier implementation able to use FFI and `dart:io`.
 class TextClassifier extends BaseTextClassifier {
+  /// Generative constructor.
   TextClassifier({required super.options});
 
+  /// Sends a `String` value to MediaPipe for classification. Uses an Isolate
+  /// on mobile and desktop, and a web worker on web, to add concurrency and avoid
+  /// blocking the UI thread while this task completes.
+  ///
+  /// See also:
+  ///  * [classify_sync] for a synchronous alternative
   @override
-  TextClassifierResult classify(String text) {
+  Future<TextClassifierResult> classify(String text) async =>
+      compute<String, TextClassifierResult>(classifySync, text);
+
+  /// Sends a `String` value to MediaPipe for classification. Blocks the main
+  /// event loop for the duration of the task, so use this with caution.
+  ///
+  /// See also:
+  ///  * [classify] for a concurrent alternative
+  @override
+  TextClassifierResult classifySync(String text) {
     // Allocate and hydrate the configuration object
     final optionsPtr = options.toStruct();
     _log.finest('optionsPtr: $optionsPtr');

packages/mediapipe-task-text/lib/src/tasks/text_classification/universal_text_classifier.dart

@@ -2,13 +2,29 @@ import 'package:mediapipe_text/mediapipe_text.dart';
 
 /// Channel to classify text via MediaPipe's "classifyText" Task.
 class TextClassifier extends BaseTextClassifier {
+  /// Generative constructor.
   TextClassifier({required super.options}) {
     throw Exception('Must use the web or FFI implementations');
   }
 
-  /// Sends a `String` value to MediaPipe for classification.
+  /// Sends a `String` value to MediaPipe for classification. Uses an Isolate
+  /// on mobile and desktop, and a web worker on web, to add concurrency and avoid
+  /// blocking the UI thread while this task completes.
+  ///
+  /// See also:
+  ///  * [classify_sync] for a synchronous alternative
   @override
-  TextClassifierResult classify(String text) {
+  Future<TextClassifierResult> classify(String text) async {
+    throw Exception('Must use the web or FFI implementations');
+  }
+
+  /// Sends a `String` value to MediaPipe for classification. Blocks the main
+  /// event loop for the duration of the task, so use this with caution.
+  ///
+  /// See also:
+  ///  * [classify] for a concurrent alternative
+  @override
+  TextClassifierResult classifySync(String text) {
     throw Exception('Must use the web or FFI implementations');
   }
 }

packages/mediapipe-task-text/test/text_classifier_test.dart

@@ -8,25 +8,32 @@ void main() {
     );
 
     test('return results from C', () {
-      final result = classifier.classify('some text');
-      expect(result.timestamp, const Duration(milliseconds: 300));
-      expect(result.classifications.length, 1);
-
-      final classifications = result.classifications.first;
-      expect(classifications.headName, 'Whatever');
-      expect(classifications.headIndex, 1);
-      expect(classifications.categories.length, 2);
-
-      final categories = result.classifications.first.categories;
-      expect(categories.first.index, 0);
-      expect(categories.first.score, closeTo(0.9, 0.001));
-      expect(categories.first.categoryName, 'some text');
-      expect(categories.first.displayName, 'some text');
+      _verifyResults(classifier.classifySync('some text'));
+    });
 
-      expect(categories.last.index, 1);
-      expect(categories.last.score, closeTo(0.7, 0.001));
-      expect(categories.last.categoryName, 'some text');
-      expect(categories.last.displayName, 'some text');
+    test('return results from C asynchronously', () async {
+      _verifyResults(await classifier.classify('some text'));
     });
   });
 }
+
+void _verifyResults(TextClassifierResult result) {
+  expect(result.timestamp, const Duration(milliseconds: 300));
+  expect(result.classifications.length, 1);
+
+  final classifications = result.classifications.first;
+  expect(classifications.headName, 'Whatever');
+  expect(classifications.headIndex, 1);
+  expect(classifications.categories.length, 2);
+
+  final categories = result.classifications.first.categories;
+  expect(categories.first.index, 0);
+  expect(categories.first.score, closeTo(0.9, 0.001));
+  expect(categories.first.categoryName, 'some text');
+  expect(categories.first.displayName, 'some text');
+
+  expect(categories.last.index, 1);
+  expect(categories.last.score, closeTo(0.7, 0.001));
+  expect(categories.last.categoryName, 'some text');
+  expect(categories.last.displayName, 'some text');
+}