How to get the length of a Cubic Bezier Curve?

Given four Vector3s, how do I compute for the length of the cubic bezier curve produced? I'm not good in math so what I'm looking for is a method something like float GetLength(Vector3 p0, Vector3 p1, Vector3 p2, Vector3 p3);

I need this so my GameObject could follow the cubic bezier curve with variable speed.

If anyone has a working code, can you share it? Thanks!