Even Azures native queue systems can guarantee that, because it gets hard to scale. You can only have one processor for any given queue, because otherwise one m

Even Azures native queue systems can guarantee that, because it gets hard to scale. You can only have one processor for any given queue, because otherwise one might take so long to process a message that others have finished processing others in the meantime. But given OPs need for at-most-once, this doesn't really seem to matter in the first place.