protected StringBuilder builder(StringBuilder builder) {

    if (builder != null) {
      return builder;
    }
    if (this.sb == null) {
      this.sb = new StringBuilder(64);
    }
    this.sb.setLength(0);
    return this.sb;
  }
protected StringBuilder builder ( StringBuilder builder ) { if ( builder != null ) { return builder ; } if ( this . sb == null ) { this . sb = new StringBuilder ( 64 ) ; } this . sb . setLength ( 0 ) ; return this . sb ; }
@param builder a local {@link StringBuilder} variable to be allocated lazily.
@return the given {@link StringBuilder} if not {@code null} or otherwise a reused {@link StringBuilder}
instance that has been reset.