writeStream.path

流正在写入的文件的路径，如 fs.createWriteStream() 的第一个参数中所指定。 如果 path 作为字符串传入，则 writeStream.path 将是字符串。 如果 path 作为 Buffer 传入，则 writeStream.path 将是 Buffer。

The path to the file the stream is writing to as specified in the first argument to fs.createWriteStream(). If path is passed as a string, then writeStream.path will be a string. If path is passed as a Buffer, then writeStream.path will be a Buffer.