how to clamp my rigidbody velocity in unity code example

Example: unityy limit rigidbody velocity

if(rigidbody.velocity.sqrMagnitude > maxVelocity)             
             {                 
               //smoothness of the slowdown is controlled by the 0.99f,                  
               //0.5f is less smooth, 0.9999f is more smooth                     
               rigidbody.velocity *= 0.99f;             
             }