Added SerializationWriterProxyFactory

lib/kiota_abstractions.dart

@@ -41,3 +41,4 @@ part 'src/serialization/parse_node_proxy_factory.dart';
 part 'src/serialization/serialization_writer.dart';
 part 'src/serialization/serialization_writer_factory.dart';
 part 'src/serialization/serialization_writer_factory_registry.dart';
+part 'src/serialization/serialization_writer_proxy_factory.dart';

lib/src/serialization/serialization_writer.dart

@@ -68,10 +68,10 @@ abstract class SerializationWriter {
   Uint8List getSerializedContent();
 
   /// Callback called before the serialization process starts.
-  void Function(Parsable)? onBeforeObjectSerialization;
+  ParsableHook? onBeforeObjectSerialization;
 
   /// Callback called after the serialization process ends.
-  void Function(Parsable)? onAfterObjectSerialization;
+  ParsableHook? onAfterObjectSerialization;
 
   /// Callback called right after the serialization process starts.
   void Function(Parsable, SerializationWriter)? onStartObjectSerialization;

lib/src/serialization/serialization_writer_proxy_factory.dart

@@ -0,0 +1,47 @@
+part of '../../kiota_abstractions.dart';
+
+abstract class SerializationWriterProxyFactory
+    implements SerializationWriterFactory {
+  SerializationWriterProxyFactory({
+    required SerializationWriterFactory concrete,
+    ParsableHook? onBefore,
+    ParsableHook? onAfter,
+    void Function(Parsable, SerializationWriter)? onStart,
+  })  : _concrete = concrete,
+        _onBefore = onBefore,
+        _onAfter = onAfter,
+        _onStart = onStart;
+
+  final SerializationWriterFactory _concrete;
+  final ParsableHook? _onBefore;
+  final ParsableHook? _onAfter;
+  final void Function(Parsable, SerializationWriter)? _onStart;
+
+  @override
+  String get validContentType => _concrete.validContentType;
+
+  @override
+  SerializationWriter getSerializationWriter(String contentType) {
+    final writer = _concrete.getSerializationWriter(contentType);
+
+    final originalBefore = writer.onBeforeObjectSerialization;
+    writer.onBeforeObjectSerialization = (p) {
+      _onBefore?.call(p);
+      originalBefore?.call(p);
+    };
+
+    final originalAfter = writer.onAfterObjectSerialization;
+    writer.onAfterObjectSerialization = (p) {
+      _onAfter?.call(p);
+      originalAfter?.call(p);
+    };
+
+    final originalStart = writer.onStartObjectSerialization;
+    writer.onStartObjectSerialization = (p, w) {
+      _onStart?.call(p, w);
+      originalStart?.call(p, w);
+    };
+
+    return writer;
+  }
+}