| Delta | The time delta (in seconds) between the last frame and the current (for all intents and purposes) | 
| GlobalNow | The number of a seconds since a set point in time. This value should match between servers and clients. If they have their timezone set correctly. | 
| Now | The time since game startup, in seconds. | 
| SmoothDelta | Like Delta but smoothed to avoid large disparities between deltas |