since v10.0.34

You can access key value pairs of various entities and Tickets via a Storage. The storage can be retrieved via the StorageHandler for Tickets or directly on the entity/ticket object with the getStorage() method.

The values inside the storage are typed. Trying to get/set a value for a key with a wrong type will result in a WrongTypeException. Setting a key for the first time will define the type of this key. A key can only have one type for each entity type.
The key value pairs are not persisted as long as the store() method hasn't been invoked. This applies to all methods that cause changes in the key value pairs.

The storage is not suitable to store mass data. The number of keys is limited to 1000 keys for each entity, that means it is not possible to use more than 1000 different keys on ticket storage or on other entity storages. It is also not recommendable to use the storage for huge data objects (megabytes).