SplitHTTP server: Add "Cache-Control: no-store" to GET response (#3652)

#3652 (comment)

transport/internet/splithttp/hub.go

@@ -184,6 +184,10 @@ func (h *requestHandler) ServeHTTP(writer http.ResponseWriter, request *http.Req
 
 		// magic header instructs nginx + apache to not buffer response body
 		writer.Header().Set("X-Accel-Buffering", "no")
+		// A web-compliant header telling all middleboxes to disable caching.
+		// Should be able to prevent overloading the cache, or stop CDNs from
+		// teeing the response stream into their cache, causing slowdowns.
+		writer.Header().Set("Cache-Control", "no-store")
 		if !h.config.NoSSEHeader {
 			// magic header to make the HTTP middle box consider this as SSE to disable buffer
 			writer.Header().Set("Content-Type", "text/event-stream")