The magnitude of this vector. Magnitude is the square root of the summed-up squares of all its components. For instance in 3D:
size = x*x + y*y + z*z
V.size is the same as sqrt(V.Dot(V)).
This value can be set at runtime, so setting size = 1 will normalize the vector.
If the size is already 0, as in the case of a degenerate vector like 0,0, then changing this value will have no effect.