Raise HTTP WriteTimeout above the request middleware timeout (closes #62)

internal/server/http.go

@@ -13,8 +13,11 @@ const (
 	httpReadTimeout = 10 * time.Second
 
 	// httpWriteTimeout is the maximum duration before timing out
-	// writes of the response.
-	httpWriteTimeout = 10 * time.Second
+	// writes of the response. It must stay above the router's
+	// requestTimeout (60s, in routes.go) so the middleware timeout
+	// fires first and returns a clean 503, rather than the transport
+	// cutting the connection at the socket write deadline.
+	httpWriteTimeout = 65 * time.Second
 
 	// httpMaxHeaderBytes is the maximum number of bytes the
 	// server will read parsing the request headers.