title: golang http handle big file upload
body: <p>I'm using the golang <code>net/http</code> package to construct a webserver.And now I have to handle big file upload which means that the server may get request with <code>Expect: 100 Continue</code>.I will not send response to the client until all data has been received.However every time I finished one request and return, the golang will send a response back by default,How can i implement this? </p>