a1ae21d - Fixes a use after free issue due to reference count corruption on the dict. std::swap was moving the reference counts, but ref counts must stay with the allocated object.

b9575a6 - An intermittent assert hit during async rehash

34b4dc0 - Improve shutdown hygene by avoiding destructors on exit. This prevents a crash on exit.

b775ec7 - Fix uninitialized variable on dictionary creation which could cause us to consume excessive memory.

8f925f4 - Prevent accidental rehash initiation when an async rehash is aborted. This can cause corruption and data loss when a snapshot is in flight

dfe092f - Respond to cancelled rehashes earlier to avoid wasted CPU

0b0a2fa - Use correct memory model for reference counting on the dict. This has no effect on X86

25119b1 - Add memory fence barriers to the replication backlog. This is important on weak memory model CPUs

a094b4a - Reduce TSAN warnings due to background time updates (this should have no production effect but reduces TSAN noise)

875b6a7 - Make async commands "opt-in" as it can change the percieved ordering across clients

455c5a8 - Resolve incorrect locking during repl backlog resize. This can cause corruption during replication. Potential cause of #423