Well, the whole point was to make ts (threadsafe) events faster.  Those are ones scheduled from off thread, like savestates.  Actually, savestates are the only consumer currently.

So before it kept calling `MoveEvents()`, creating a mutex (which isn't slow but even so), and checking `tsFirst` and `allocatedTsEvents`.  I wanted to cut that down to just a single check without a mutex and saving a function call.  It's a small gain but when fast forwarding it adds up, and Advance is called not inoften.

-[Unknown]