interface kvs {
// Retrieves a value from the persistent store for a given key.
// Returns none if the key does not exist.
store-get: func(key: string) -> option<string>;
// Sets a value in the persistent store for a given key.
// This will create a new entry or overwrite an existing one.
store-set: func(key: string, value: string);
// Deletes a key-value pair from the store.
store-delete: func(key: string);
// Checks if a key exists in the store.
store-exists: func(key: string) -> bool;
// Returns a list of all keys currently in the store.
store-list-keys: func() -> list<string>;
}