Only make a best-effort to release mStacks
Only make a best-effort to release mStacks

It doesn't *actually* matter, and getting rid of the defer is worth
~80ns of perf.

cognusion/goji,Invacio/goji,dbmlabs/goji,vsco/goji,zenazn/goji,vanackere/slim,beni55/goji,w4ngyi/goji,yangou/goji,tchssk/goji,unixorn/goji