anchor.diff:    double get w;
   
     /// Extract the sign bits from each lane return them in the first 4 bits.
  +  /// "x" lane is bit 0.
  +  /// "y" lane is bit 1.
  +  /// "z" lane is bit 2.
  +  /// "w" lane is bit 3.
     int get signMask;
   
     /// Mask passed to [shuffle] or [shuffleMix].
  
positive.code:   external factory Float32x4List(int length);
  
    /**
     * Creates a [Float32x4List] with the same size as the [elements] list
     * and copies over the elements.
     */
    external factory Float32x4List.fromList(List<Float32x4> elements);
  
negative.code:    * the length of [buffer].
     *
     * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
     * [BYTES_PER_ELEMENT].
     */
    external factory Int32x4List.view(ByteBuffer buffer,
                                        [int offsetInBytes = 0, int length]);
  