backends

type Item interface {
	// Key returns the unique identical key for this item.
	// Key will be used to decide the partial order. Currently
	// it's string type and cannot be changed.
	Key() string
	// Marshal marshals the item.
	Marshal() ([]byte, error)
}

type Revisioner interface {
	// Revision returns the current revision.
	Revision() int64
	// Incr increases the current revision and returns it.
	Incr() int64
}