A difficulty here, however, is that the TransformStreamDefaultController does not have a ready promise mechanism like Writers do; so the TransformStream implementation would need to implement a polling mechanism to periodically check when controller.desiredSize becomes positive again.
The Department for Environment, Food and Rural Affairs said: "Our chalk streams are one of Britain's most nature rich habitats and are embedded in our plans to reform the water industry.，这一点在Line官方版本下载中也有详细论述
5 transform chain，更多细节参见im钱包官方下载
Tony Jolliffe BBC