Add non-streaming ASR examples for Dart API (#1007)

dart-api-examples/vad/bin/init.dart

@@ -0,0 +1,29 @@
+import 'dart:io';
+import 'dart:isolate';
+import 'package:path/path.dart' as p;
+import 'package:sherpa_onnx/sherpa_onnx.dart' as sherpa_onnx;
+
+Future<void> initSherpaOnnx() async {
+  var uri = await Isolate.resolvePackageUri(
+      Uri.parse('package:sherpa_onnx/sherpa_onnx.dart'));
+
+  if (uri == null) {
+    print('File not found');
+    exit(1);
+  }
+
+  String platform = '';
+
+  if (Platform.isMacOS) {
+    platform = 'macos';
+  } else if (Platform.isLinux) {
+    platform = 'linux';
+  } else if (Platform.isWindows) {
+    platform = 'windows';
+  } else {
+    throw UnsupportedError('Unknown platform: ${Platform.operatingSystem}');
+  }
+
+  final libPath = p.join(p.dirname(p.fromUri(uri)), '..', platform);
+  sherpa_onnx.initBindings(libPath);
+}