StorageAdded if this is a new entry in the storage.

StorageDeleted if the storage was deleted.

StorageModified if the value has been modified.

StorageModifiedAgain if the value has been modified before in the txn.

StorageUnchanged if the data has not changed.

Contract is the instance being called.

TxContext is the context of the transaction.

Host is the execution host.

Runtime can process contracts.

StorageStatus is the status of the storage access.