@callback cached_mode() :: nil | :local | :broadcast | :observer

@callback get_keys_by_node(node()) :: list()

@callback list_active_nodes() :: list()

@callback list_data_by_node_key(node() | String.t(), String.t(), Keyword.t()) :: list()

@callback push_data(any()) :: :ok

@callback subscribe_for_new_data(node() | String.t(), String.t()) ::
  :ok | {:error, term()}

@callback subscribe_for_new_keys() :: :ok | {:error, term()}

@callback unsubscribe_for_new_data(node() | String.t(), String.t()) :: :ok

@callback update_data_retention_period(non_neg_integer()) :: :ok