Support EnableCloseConnection (#183)

client.go

@@ -1277,6 +1277,7 @@ func (c *Client) roundTrip(r *Request) (resp *Response, err error) {
 		ContentLength: contentLength,
 		Body:          reqBody,
 		GetBody:       r.GetBody,
+		Close:         r.close,
 	}
 	for _, cookie := range r.Cookies {
 		req.AddCookie(cookie)

request.go

@@ -43,6 +43,7 @@ type Request struct {
 	isMultiPart              bool
 	forceChunkedEncoding     bool
 	isSaveResponse           bool
+	close                    bool
 	error                    error
 	client                   *Client
 	uploadCallback           UploadCallback
@@ -1052,3 +1053,14 @@ func (r *Request) SetClient(client *Client) *Request {
 func (r *Request) GetClient() *Client {
 	return r.client
 }
+
+// EnableCloseConnection closes the connection after sending this
+// request and reading its response if set to true in HTTP/1.1 and
+// HTTP/2.
+//
+// Setting this field prevents re-use of TCP connections between
+// requests to the same hosts event if EnableKeepAlives() were called.
+func (r *Request) EnableCloseConnection() *Request {
+	r.close = true
+	return r
+}

request_wrapper.go

@@ -481,3 +481,9 @@ func SetDownloadCallback(callback DownloadCallback) *Request {
 func SetDownloadCallbackWithInterval(callback DownloadCallback, minInterval time.Duration) *Request {
 	return defaultClient.R().SetDownloadCallbackWithInterval(callback, minInterval)
 }
+
+// EnableCloseConnection is a global wrapper methods which delegated
+// to the default client, create a request and EnableCloseConnection for request.
+func EnableCloseConnection() *Request {
+	return defaultClient.R().EnableCloseConnection()
+}