code: @Override
  	public char getDataLength() {
  		if (this.unknownAttributes == null) {
  			return 0;
  		}
  
  		char length = (char) unknownAttributes.size();
  		if ((length % 2) != 0) {
  			length++;
  		}
  		return (char) (length * 2);
  	}
docs: Returns the length (in bytes) of this attribute's body.
  
  If the number of unknown attributes is an odd number, one of the
  attributes MUST be repeated in the list, so that the total length of the
  list is a multiple of 4 bytes.
  
  @return the length of this attribute's value (a multiple of 4).