example

type Channel string

type ID uint64

type Message struct {
	// Each message has a unique ID.
	ID ID

	// A message belongs to a specific channel.
	Channel Channel

	// And has a body
	Body string
}

type Store interface {
	// Inserts an entry in the store. Returns an error if an entry with greater or
	// equal ID was already inserted.
	Put(msg Message) error

	// Returns a slice of all messages in the specified channels, from the
	// specified ID to the message with most recent ID. All messages will have IDs
	// such that `sinceID < ID <= mostRecentID`.
	EntriesSince(sinceID ID, channel Channel) (ID, []Message)

	// Returns the ID of the most recently inserted message.
	MostRecentID() ID

	// Returns the number of messages in the store.
	NumEntries() int

	// Returns all messages across all channels as a single slice,
	// sorted by ID.
	AsSlice() []Message

	// Returns the maximum number of messages in the store.
	MessageLimit() int
}