Aggregated startup ms

Summary: ^

Reviewed By: antonk52

Differential Revision: D50012359

fbshipit-source-id: f71f57e1493e6f9f662e9af24a0f8d0ae1229b1b

desktop/flipper-server/src/index.tsx

@@ -275,6 +275,8 @@ async function start() {
     )} (${serverStartedMS} ms)`,
   );
 
+  const startupMS = t10 - t0;
+
   tracker.track('server-bootstrap-performance', {
     loggerInitializedMS,
     keytarLoadedMS,
@@ -286,6 +288,7 @@ async function start() {
     developmentServerAttachedMS,
     serverStartedMS,
     launchedMS,
+    startupMS,
   });
 }