[oslo.messaging] Heartbeat in pthread

Hello,

I completely miss the deprecation of heartbeat_in_pthread in oslo.messaging [1].

We heavily rely on this parameter downstream and our opinion is that it should be set to True by default. We use it for both wsgi services and agents (nova-compute, neutron agents, etc.).

I understand that eventlet will be dropped in the future, but should we set heartbeat_in_pthread to True by default until then?

Regards,

Arnaud.

[1] https://review.opendev.org/c/openstack/oslo.messaging/+/925778