TF-495 Create a Benchmark object to calculate rendering time

core/lib/core.dart

@@ -26,6 +26,7 @@ export 'presentation/utils/html_transformer/transform_configuration.dart';
 export 'presentation/utils/html_transformer/dom/add_tooltip_link_transformers.dart';
 export 'data/utils/device_manager.dart';
 export 'utils/app_logger.dart';
+export 'utils/benchmark.dart';
 
 // Views
 export 'presentation/views/text/slogan_builder.dart';

core/lib/utils/benchmark.dart

@@ -0,0 +1,29 @@
+
+import 'package:core/utils/app_logger.dart';
+
+class _Benchmark {
+  final Map<String, int> _starts = <String, int>{};
+
+  void start(dynamic id) {
+    final String benchId = id.toString();
+    if (_starts.containsKey(benchId)) {
+      log('_Benchmark::start(): Benchmark already have comparing with id=$benchId in time');
+    } else {
+      _starts[benchId] = DateTime.now().microsecondsSinceEpoch;
+    }
+  }
+
+  double end(dynamic id) {
+    final String benchId = id.toString();
+    if (!_starts.containsKey(benchId)) {
+      throw Exception('In Benchmark not placed comparing with id=$benchId');
+    }
+    final double diff = (DateTime.now().microsecondsSinceEpoch - _starts[benchId]!) / 1000;
+    final String info = '$benchId need ${diff}ms';
+    log('_Benchmark::end(): $info');
+    _starts.remove(benchId);
+    return diff;
+  }
+}
+
+final _Benchmark bench = _Benchmark();