messagewindow

type MessageWindow[S constraints.Integer, T any] interface {
	// Send message into this window.
	// This method won't block and concurrency safe.
	//
	// Sequence number must start with 0.
	//
	// If this window have been closed by the consumer, returns ErrClosedMessageWindow
	Send(sequence S, msg T) error

	// Consume message from this window.
	//
	// Because the aim of this window is to provide sequential message stream, only one goroutine should consume messages.
	// If multiple goroutines consume, the result is not guaranteed.
	//
	// If this window have been closed (= end of sequence), this method returns io.EOF.
	// Also, this method block until next message, context cancelation, or close.
	Consume(ctx context.Context) (S, T, error)

	// Close means the end of message sequence (if sender call) or means receiver's will to not receive message anymore.
	// At least one of sender or receiver must call Close to avoid resource leakage.
	// Concurrent / duplicated call of Close() is fine.
	Close()
}