success verifiedcritical

This queue and its counterpart are Hub's telemetry for MailerQ. A result carries the envelope, the recipient, every attempt with its state, outcome, codes, timings, the sending and receiving addresses, and any custom property the message carried. Reading is destructive — a consumer takes the message. That has a consequence worth stating in the product: whoever consumes this queue is the only one who ever sees those results. If a customer's own application also reads it, Hub and the customer each get a random half of the picture, and neither can tell. Either Hub is the sole consumer, or the engine must be configured with separate queue names for them. And if nobody reads it, it grows. We measured the small version of that: 17 messages from an afternoon of probing. On a production node it is the documented way to fill a broker.