*
   * @since 20.0
   */
  public static final class LinearTransformationBuilder {

    private final double x1;
    private final double y1;

    private LinearTransformationBuilder(double x1, double y1) {
      this.x1 = x1;
      this.y1 = y1;
    }

    /**
     * Finish building an instance which also maps {@code x = x2} to {@code y = y2}. These values

	VADDPD.RN_SAE X3, X2, K1, X1     // ERROR "unsupported rounding"
	VADDPD.RU_SAE Y3, Y2, K1, Y1     // ERROR "unsupported rounding"
	VADDPD.RD_SAE Y3, Y2, K1, Y1     // ERROR "unsupported rounding"
	VADDPD.RZ_SAE Y3, Y2, K1, Y1     // ERROR "unsupported rounding"
	VADDPD.RN_SAE Y3, Y2, K1, Y1     // ERROR "unsupported rounding"
	// Unsupported SAE.

	VPOPCNTQ Y5, K2, Y1                                // 62f2fd2a55cd
	VPOPCNTQ Y17, K2, Y1                               // 62b2fd2a55c9
	VPOPCNTQ Y13, K2, Y1                               // 62d2fd2a55cd
	VPOPCNTQ 7(AX)(CX*4), K2, Y1                       // 62f2fd2a558c8807000000
	VPOPCNTQ 7(AX)(CX*1), K2, Y1                       // 62f2fd2a558c0807000000

		}
		return v, err
	}

	duration := ts2.Sub(ts1)
	y1, m1, d1 := ts1.Date()
	y2, m2, d2 := ts2.Date()

	switch timePart {
	case timePartYear:
		dy := int64(y2 - y1)
		if m2 > m1 || (m2 == m1 && d2 >= d1) {
			return FromInt(dy), nil
		}
		return FromInt(dy - 1), nil
	case timePartMonth:
		m1 += time.Month(12 * y1)
		m2 += time.Month(12 * y2)

		return FromInt(int64(m2 - m1)), nil