seenstate

type SeenState interface {
	// Set() (re)sets the given level to the given value.
	SetLevel(level string, top int64) error
	// GetAll() returns a "simple" map of the current levels.
	GetAllLevels() (map[string]int64, error)
	// FilterBySeen filters notifications already seen, keep track
	// of them as well.
	FilterBySeen([]protocol.Notification) ([]protocol.Notification, error)
	// Close closes state.
	Close()
}