• Instead of using broadcast/1, broadcast_request/1 is used and the message is only considered processed if broadcast_request/1 succeeds. If the message is handled with success, an XACK is sent to the server.

Options processed:

block +Seconds

Causes XREADGROUP to return with timeout when no messages arrive within Seconds. On a timeout, xidle_group/5 is called which will try to handle messages to other consumers pending longer than Seconds. Choosing the time depends on the application. Notably:

• Using a time shorter than the required processing time will make the job migrate from consumer to consumer until max_deliveries(Count) is exceeded. Note that the original receiver does not notice that the job is claimed and thus multiple consumers may ultimately answer the message.
• Using a too long time causes an unnecessarily long delay if a node fails.

max_deliveries(+Count)

Re-deliver (using XCLAIM) a message max Count times. Exceeding this calls xhook/2. Default Count is 3.

max_claim(+Count)

Do not claim more than Count messages during a single idle action. Default is 10.