Function newReader

db/journal/reader.go:19–26

(ctx context.Context, q *Queue, head, tail ID)

}

func newReader(ctx context.Context, q *Queue, head, tail ID) *Reader {
	return &Reader{
		ctx:    ctx,
		q:      q,
		cursor: tail - 1,
		stop:   head,
	}
}

func (r *Reader) Read(b []byte) (int, error) {
	if len(r.buffer) == 0 {