MMKVPMarshaller heap corruption

[Aphemuru]

If you pass an empty size MatchMakingKeyValuePair_t[] array (instead of null) to any of the RequestXYZList methods in SteamMatchmakingServers, it will cause heap corruption.

Why: it will allocate a zero-size block of memory using Marshal.AllocHGlobal. I'm sure the actual returned size isn't zero, because it returns a valid pointer, but the problem is it writes 8 bytes onto this. When it gets freed it causes a heap corruption error.

Solution: Simply check if the array is empty, and do not allocate anything if that's the case.