TF-657 Add headers and keywords property when get email content

model/lib/extensions/email_extension.dart

@@ -13,8 +13,14 @@ extension EmailExtension on Email {
 
   bool get hasStarred => keywords?.containsKey(KeyWordIdentifier.emailFlagged) == true;
 
+  bool get hasMdnSent => keywords?.containsKey(KeyWordIdentifier.mdnSent) == true;
+
   bool get withAttachments => hasAttachment == true;
 
+  bool get needShowNotificationMessageReadReceipt {
+    return !hasMdnSent && headers.readReceiptHasBeenRequested;
+  }
+
   Set<String> getRecipientEmailAddressList() {
     final listEmailAddress = Set<String>();
     final listToAddress = to.getListAddress() ?? [];

model/lib/extensions/list_email_header_extension.dart

@@ -0,0 +1,14 @@
+
+import 'package:jmap_dart_client/jmap/mail/email/email_header.dart';
+import 'package:model/email/email_property.dart';
+
+extension ListEmailHeaderExtension on Set<EmailHeader>? {
+  bool get readReceiptHasBeenRequested {
+    try {
+      final headerMdn = this?.firstWhere((header) => header.name == EmailProperty.headerMdnKey);
+      return headerMdn != null;
+    } catch (e) {
+      return false;
+    }
+  }
+}