docs: public IStringBuffer append( String str )
      {
          if ( str == null )
              throw new NullPointerException();
          //check the necessary to resize the buffer.
          if ( count + str.length() > buff.length ) {
              resizeTo( (count + str.length()) * 2 + 1 );
          }
          
          for ( int j = 0; j < str.length(); j++ ) {
              buff[count++] = str.charAt(j);
          }
          
          return this;
      }