When is it safe to leave sc_writewait uninitialized? The field seems to have emerged in the middle of RE24, and I don't see any flags which say it should/should not be used.
Since not setting it crashed back-relay in ITS#8428, does that mean everything which creates a slap_callback should set it? Seems unfortunate for third-party modules... Also, I think this should be documented. -- Hallvard
