Improving interpolation

Here's how our new interpolation will work, inspired by the methods employed in the Source game engine:

• As we receive network states, we buffer them up

• Each network state is timestamped with network time

• We subtract a value from time to find a time in the past (in source, this value is 0.1 by default—so entities are always shown one tenth of a second in the past)

• We find the two states on either side of this time value, and interpolate between them

• Let's get started

First, we need some kind of struct to store a snapshot of the network state:

// a snapshot of values received over the network
private struct networkState
{
  public Vector3 Position;
  public double Timestamp;
  
  public networkState( Vector3 pos, double time )
  {
    this.Position = pos;
    this.Timestamp = time;
  }
}

We'll keep a buffer of these to interpolate in between. Note our use of arrays for this purpose. We use a statically sized array for better performance (if we used a List, internally the List...