docs: public int getStartNextPropertyKey(int iIndex, String strMessage)
      {
          for (iIndex = iIndex + 1; iIndex < strMessage.length(); iIndex++)
          {
              char chChar = strMessage.charAt(iIndex);
              if (this.isEndChar(chChar))
                  break;
          }
          if (iIndex >= strMessage.length())
              return -1;
          int iNextProperty = strMessage.indexOf(END_OF_KEY_CHAR, iIndex);
          if (iNextProperty == -1)
              return -1;  // Not found
          for (int i = iNextProperty - 1; i >= 0; i--)
          {
              char chChar = strMessage.charAt(i);
              if (this.isEndChar(chChar))
              {   // Key always starts on a new line.
                  for (int k = i + 1; k < strMessage.length(); k++)
                  {   // Now go forward to the first character.
                      chChar = strMessage.charAt(k);
                      if (!this.isLeadingWhitespace(chChar))
                      {
                          return k;
                      }
                  }
              }
          }
          return -1;
      }