writableStream.getWriter()
创建并返回一个新的写入器实例，可用于将数据写入 WritableStream。
¥Creates and returns a new writer instance that can be used to write
data into the WritableStream.
创建并返回一个新的写入器实例，可用于将数据写入 WritableStream。
¥Creates and returns a new writer instance that can be used to write
data into the WritableStream.