code: public static byte[] toByteArray(final String s) {
  		final byte[] byteArray = new byte[s.length()];
  		// This needs to be fast.
  		for(int i = s.length(); i-- != 0;) {
  			assert s.charAt(i) < (char)0x80 : s.charAt(i);
  			byteArray[i] = (byte)s.charAt(i);
  		}
  		return byteArray;
  	}
docs: Returns a byte-array representation of an ASCII string.
  
  <p>This method is significantly faster than those relying on character encoders, and it allocates just
  one object&mdash;the resulting byte array.
  
  @param s an ASCII string.
  @return a byte-array representation of {@code s}.
  @throws AssertionError if assertions are enabled and some character of {@code s} is not ASCII.