AdditionalData map not populated for collections #295
Description
DefaultSerializer.setChildAdditionalData() lacks support of collections. As you can see, only a HashMap (why not just Map???) and IJsonBackedObject are supported. As a result all other collections fail to get additionalDataManager field populated. For instance, DriveItems fetched with GET /user/{userId}/drive/root/delta don't have this field populated for createdBy.user object. Same object's property is populated for Drive as response's value field is scalar.
Expected behavior
DriveItem.createdBy.user.additionalDataManager should contain user email
Actual behavior
DriveItem.createdBy.user.additionalDataManager is empty
Steps to reproduce the behavior
final String json = "{\n"
+ " \"@odata.context\": \"https://graph.microsoft.com/v1.0/$metadata#users('02008492-3fec-4ce4-bb54-980ad856856f')/drive/root/children\",\n"
+ " \"value\": [\n"
+ " {\n"
+ " \"createdBy\": {\n"
+ " \"user\": {\n"
+ " \"email\": \"the@email.com\",\n"
+ " \"id\": \"02008492-3fec-4ce4-bb54-980ad856856f\",\n"
+ " \"displayName\": \"John Doe\"\n"
+ " }\n"
+ " }\n"
+ " }\n"
+ " ]\n"
+ "}";
final DefaultSerializer serializer = new DefaultSerializer(new DefaultLogger());
final DriveItemDeltaCollectionResponse deserialized = serializer
.deserializeObject(json, DriveItemDeltaCollectionResponse.class);
System.out.println(deserialized.value.get(0).createdBy.user.additionalDataManager());```