Interface SerializedItemDescriptor

True if this a placeholder (tombstone) for a deleted item.

If so, #serializedItem will still contain a string representing the deleted item, but the persistent store implementation has the option of not storing it if it can represent the placeholder in a more efficient way.

Returns the data item's serialized representation. This will never be null when storing an item; for a deleted item placeholder, it will contain a special value that can be stored if necessary. When reading an item from a store this could be null. (see #deleted()).

The version of the data.