docs: public static int commonPrefix(String text1, String text2) {
          // Performance analysis: http://neil.fraser.name/news/2007/10/09/
          int n = Math.min(text1.length(), text2.length());
          for (int i = 0; i < n; i++) {
              if (text1.charAt(i) != text2.charAt(i)) {
                  return i;
              }
          }
          return n;
      }