ReadonlyactionOptional ReadonlydeliveryOptional Readonlydeliverykey of an existing Delivery.
Either `deliveryId` or `deliveryKey` must be provided.
Optional ReadonlyfieldsObject containing the Custom Fields fields for the Delivery.
Required if at least one Custom Field is defined as required in the `fieldDefinitions` of the referenced [Type](ctp:api:type:Type).
Optional ReadonlytypeDefines the Type that extends the Delivery with Custom Fields. If absent, any existing Type and Custom Fields are removed from the Delivery.
idof an existing Delivery.