spool

type Spool interface {
	// StoreMessage stores a message in the user's spool.
	StoreMessage(u, msg []byte) error

	// StoreSURBReply stores a SURBReply in the user's spool.
	StoreSURBReply(u []byte, id *[constants.SURBIDLength]byte, msg []byte) error

	// Get optionally deletes the first entry in a user's spool, and returns
	// the (new) first entry.  Both messages and SURBReplies may be returned.
	Get(u []byte, advance bool) (msg, surbID []byte, remaining int, err error)

	// Remove removes the spool identified by the username from the database.
	Remove(u []byte) error

	// VacuumExpired removes spools for identities not in the provided
	// set of connected clients.
	VacuumExpired(ignoreIdentities map[[constants.RecipientIDLength]byte]interface{}) error

	// Close closes the Spool instance.
	Close()
}