Enable hooks globally when the flag is on

This is a DEV only feature.

Author: sebmarkbage

packages/react-server/src/ReactFlightServerConfigDebugNode.js

@@ -8,3 +8,23 @@
  */
 
 import {createAsyncHook} from './ReactFlightServerConfig';
+import {enableAsyncDebugInfo} from 'shared/ReactFeatureFlags';
+
+if (__DEV__ && enableAsyncDebugInfo) {
+  // Initialize the tracing of async operations.
+  // We do this globally since the async work can potentially eagerly
+  // start before the first request and once requests start they can interleave.
+  // In theory we could enable and disable using a ref count of active requests
+  // but given that typically this is just a live server, it doesn't really matter.
+  createAsyncHook({
+    init(asyncId: number, type: string, triggerAsyncId: number): void {
+      // TODO
+    },
+    promiseResolve(asyncId: number): void {
+      // TODO
+    },
+    destroy(asyncId: number): void {
+      // TODO
+    },
+  }).enable();
+}