diff --git a/Build/index.ts b/Build/index.ts
index 4c17fc2e..dd61fe2e 100644
--- a/Build/index.ts
+++ b/Build/index.ts
@@ -53,13 +53,13 @@ import { TaskResult } from './lib/trace-runner';
 
     const buildInternalReverseChnCIDRPromise = new Promise<TaskResult>(resolve => {
       const handleMessage = (e: MessageEvent<TaskResult>) => {
-        buildInternalReverseChnCIDRWorker.unref();
         const { data } = e;
 
         buildInternalReverseChnCIDRWorker.postMessage('exit');
+        buildInternalReverseChnCIDRWorker.removeEventListener('message', handleMessage);
         resolve(data);
       };
-      buildInternalReverseChnCIDRWorker.addEventListener('message', handleMessage, { once: true });
+      buildInternalReverseChnCIDRWorker.addEventListener('message', handleMessage);
       buildInternalReverseChnCIDRWorker.postMessage('build');
     });
 
diff --git a/Build/workers/build-internal-reverse-chn-cidr-worker.ts b/Build/workers/build-internal-reverse-chn-cidr-worker.ts
index f87dac42..4a04f3cc 100644
--- a/Build/workers/build-internal-reverse-chn-cidr-worker.ts
+++ b/Build/workers/build-internal-reverse-chn-cidr-worker.ts
@@ -1,11 +1,18 @@
 declare const self: Worker;
 
-self.addEventListener('message', async (e: MessageEvent<'build' | 'exit'>) => {
+import { buildInternalReverseChnCIDR } from '../build-internal-reverse-chn-cidr';
+
+// preload the task
+const promise = buildInternalReverseChnCIDR();
+
+const handleMessage = async (e: MessageEvent<'build' | 'exit'>) => {
   if (e.data === 'build') {
-    const { buildInternalReverseChnCIDR } = await import('../build-internal-reverse-chn-cidr');
-    const stat = await buildInternalReverseChnCIDR();
+    const stat = await promise;
     postMessage(stat);
   } else if (e.data === 'exit') {
-    process.exit(0);
+    self.removeEventListener('message', handleMessage);
+    self.unref();
   }
-}, { once: true });
+};
+
+self.addEventListener('message', handleMessage);