Returns the system uptime of your computer in seconds, with millisecond precision.
seconds = GetTime()
- number - The current system uptime in seconds, e.g. 60123.558
- This value is only updated once per rendered frame. Finer-grained timers are available using GetTimePreciseSec() or debugprofilestop().
- It is possible for this function to return identical values across consecutive frames if a low resolution timing method is in use while running at a high framerate.
- Patch 4.3.0 / API (2011-11-29): Now only updates once every OnUpdate 
- Patch 1.1.0 / API (2004-11-07): Added.