Comparison

mod_s2s: Store real stanzas in session.sendq, rather than strings This is the "right" thing to do. Strings were more memory-efficient, but e.g. bypassed stanza filters at reconnection time. Also not being stanzas prevents us from potential future work, such as merging sendq with mod_smacks. Regarding performance: we should counter the probable negative effect of this change with other positive changes that are desired anyway - e.g. a limit on the size of the sendq, improved in-memory representation of stanzas, s2s backoff (e.g. if a remote server is persistently unreachable, cache this failure for a while and don't just keep forever queuing stanzas for it).