Netplay stutter

[bbbradsmith]

Netplay works but will stutter frequently.

My theory is that savestates start to diverge after a restore. There may be some non-functional data, like a timer or something that doesn't deterministically follow from a savestate restore.

To test this, put in code to dump a new uncompressed serialization each frame. Do some savestate restores and compare the data of the dumps frame by frame to see if/when they diverge. Once found, review the memory snapshot code to find the culprit.

[bbbradsmith]

Tried a few different methods to compare savestate and restore, once the divergences were mostly hammered out netplay has become quite reasonable.