Enable hooks globally when the flag is on

This is a DEV only feature.

packages/react-server/src/ReactFlightServer.js

@@ -70,6 +70,7 @@ import {
   requestStorage,
   prepareHostDispatcher,
   createHints,
+  initAsyncDebugInfo,
 } from './ReactFlightServerConfig';
 
 import {
@@ -117,6 +118,8 @@ import binaryToComparableString from 'shared/binaryToComparableString';
 
 import {SuspenseException, getSuspendedThenable} from './ReactFlightThenable';
 
+initAsyncDebugInfo();
+
 const ObjectPrototype = Object.prototype;
 
 type JSONValue =

packages/react-server/src/ReactFlightServerConfigDebugNode.js

@@ -8,3 +8,25 @@
  */
 
 import {createAsyncHook} from './ReactFlightServerConfig';
+import {enableAsyncDebugInfo} from 'shared/ReactFeatureFlags';
+
+// 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.
+export function initAsyncDebugInfo(): void {
+  if (__DEV__ && enableAsyncDebugInfo) {
+    createAsyncHook({
+      init(asyncId: number, type: string, triggerAsyncId: number): void {
+        // TODO
+      },
+      promiseResolve(asyncId: number): void {
+        // TODO
+      },
+      destroy(asyncId: number): void {
+        // TODO
+      },
+    }).enable();
+  }
+}

packages/react-server/src/ReactFlightServerConfigDebugNoop.js

@@ -8,3 +8,4 @@
  */
 
 // Exported for runtimes that don't support Promise instrumentation for async debugging.
+export function initAsyncDebugInfo(): void {}