docs: public static boolean isBlank(CharSequence sourceSequence) {
          int sequenceLength;
          if (sourceSequence == null || (sequenceLength = sourceSequence.length()) == 0) {
              return true;
          }
          for (int i = 0; i < sequenceLength; i++) {
              if ((Character.isWhitespace(sourceSequence.charAt(i)) == false)) {
                  return false;
              }
          }
          return true;
      }