KnownStringMetadataFieldsDeliveryDate Field

"Delivery-Date" MIME (header) and image document associated metadata field. There is also a DateTimeMetadataFields.DeliveryDate version of this field, and this field is only set if field cannot be parsed into a valid DateTime.

[KnownMetadataAttribute(IsEmailType = true, IsImageType = true)]
public const string DeliveryDate = "DeliveryDate"