request.end([data[, encoding]][, callback])

• data <string> | <Buffer> | <Uint8Array>

• encoding <string>

• callback <Function>

• 返回：<this>

  ¥Returns: <this>

完成发送请求。如果正文的任何部分未发送，则会将它们刷新到流中。如果请求被分块，则将发送终止的 '0\r\n\r\n'。

¥Finishes sending the request. If any parts of the body are unsent, it will flush them to the stream. If the request is chunked, this will send the terminating '0\r\n\r\n'.

如果指定了 data，则相当于调用 request.write(data, encoding) 后跟 request.end(callback)。

¥If data is specified, it is equivalent to calling request.write(data, encoding) followed by request.end(callback).

如果指定了 callback，则将在请求流完成时调用。

¥If callback is specified, it will be called when the request stream is finished.