实现可读流

¥Implementing a readable stream

stream.Readable 类被扩展以实现 Readable 流。

¥The stream.Readable class is extended to implement a Readable stream.

自定义 Readable 流必须调用 new stream.Readable([options]) 构造函数并实现 readable._read() 方法。

¥Custom Readable streams must call the new stream.Readable([options]) constructor and implement the readable._read() method.