ZLibEncoder({bool gzip: false, int level: ZLibOption.DEFAULT_LEVEL, int windowBits: ZLibOption.DEFAULT_WINDOW_BITS, int memLevel: ZLibOption.DEFAULT_MEM_LEVEL, int strategy: ZLibOption.STRATEGY_DEFAULT, List<int> dictionary: null, bool raw: false})

Source 

ZLibEncoder({this.gzip: false,
            this.level: ZLibOption.DEFAULT_LEVEL,
            this.windowBits: ZLibOption.DEFAULT_WINDOW_BITS,
            this.memLevel: ZLibOption.DEFAULT_MEM_LEVEL,
            this.strategy: ZLibOption.STRATEGY_DEFAULT,
            this.dictionary: null,
            this.raw: false}) {
  _validateZLibeLevel(level);
  _validateZLibMemLevel(memLevel);
  _validateZLibStrategy(strategy);
  _validateZLibWindowBits(windowBits);
}