process: add .initialEventLoop

PR-URL: #28941

Author: ChALkeR

lib/internal/bootstrap/node.js

@@ -92,6 +92,22 @@ const rawMethods = internalBinding('process_methods');
   };
 }
 
+{
+  let perf_hooks;
+  let initialEventLoop = true;
+  ObjectDefineProperty(process, 'initialEventLoop', {
+    enumerable: true,
+    configurable: false,
+    get() {
+      if (initialEventLoop) {
+        if (!perf_hooks) perf_hooks = require('perf_hooks');
+        initialEventLoop = perf_hooks.performance.nodeTiming.loopStart < 0;
+      }
+      return initialEventLoop;
+    }
+  });
+}
+
 const credentials = internalBinding('credentials');
 if (credentials.implementsPosixCredentials) {
   process.getuid = credentials.getuid;