As a client I would like to get the current approximate number of pending messages for a durable subscription. All existing providers give this information via a custom API or JMX at present.
My first comment on JMS_SPEC-15 also applies here.
I'm merging this proposal with two more general proposals:
JMS_SPEC-59 - which covers general non-JMX metadata queries
JMS_SPEC-18 - which covers general JMX facilities
I'm going to close this issue as a duplicate of those. Feel free to contribute comments to those issues.