code: public static byte[] flip(final byte[] data, final int index) {
  		return get(data, index) ? unset(data, index) : set(data, index);
  	}
docs: Flip the bit at the given index.
  
  @param data the data array.
  @param index the index of the bit to flip.
  @return the input array, for command chaining
  @throws IndexOutOfBoundsException if the index is
  {@code index >= max || index < 0}.
  @throws NullPointerException if the {@code data} array is {@code null}.