diff --git a/cmd/workers-assets-gen/assets/common/shim.mjs b/cmd/workers-assets-gen/assets/common/shim.mjs
index a3a483a..f632a07 100644
--- a/cmd/workers-assets-gen/assets/common/shim.mjs
+++ b/cmd/workers-assets-gen/assets/common/shim.mjs
@@ -1,8 +1,6 @@
 import "./wasm_exec.js";
 import { connect } from 'cloudflare:sockets';
 
-const go = new Go();
-
 let mod;
 
 globalThis.tryCatch = (fn) => {
@@ -22,6 +20,8 @@ export function init(m) {
 }
 
 async function run(ctx) {
+  const go = new Go();
+
   let ready;
   const readyPromise = new Promise((resolve) => {
     ready = resolve;
diff --git a/handler.go b/handler.go
index 87398bb..8814f3b 100644
--- a/handler.go
+++ b/handler.go
@@ -12,7 +12,10 @@ import (
 	"github.com/syumai/workers/internal/runtimecontext"
 )
 
-var httpHandler http.Handler
+var (
+	httpHandler http.Handler
+	closeCh     = make(chan struct{})
+)
 
 func init() {
 	var handleRequestCallback js.Func
@@ -40,6 +43,15 @@ func init() {
 	jsutil.Binding.Set("handleRequest", handleRequestCallback)
 }
 
+type appCloser struct {
+	io.ReadCloser
+}
+
+func (c *appCloser) Close() error {
+	defer close(closeCh)
+	return c.ReadCloser.Close()
+}
+
 // handleRequest accepts a Request object and returns Response object.
 func handleRequest(reqObj js.Value, runtimeCtxObj js.Value) (js.Value, error) {
 	if httpHandler == nil {
@@ -55,7 +67,7 @@ func handleRequest(reqObj js.Value, runtimeCtxObj js.Value) (js.Value, error) {
 	w := &jshttp.ResponseWriter{
 		HeaderValue: http.Header{},
 		StatusCode:  http.StatusOK,
-		Reader:      reader,
+		Reader:      &appCloser{reader},
 		Writer:      writer,
 		ReadyCh:     make(chan struct{}),
 	}
@@ -79,5 +91,7 @@ func Serve(handler http.Handler) {
 	}
 	httpHandler = handler
 	ready()
-	select {}
+	select {
+	case <-closeCh:
+	}
 }
diff --git a/internal/jshttp/responsewriter.go b/internal/jshttp/responsewriter.go
index 90fd9d6..fe3dbac 100644
--- a/internal/jshttp/responsewriter.go
+++ b/internal/jshttp/responsewriter.go
@@ -10,7 +10,7 @@ import (
 type ResponseWriter struct {
 	HeaderValue http.Header
 	StatusCode  int
-	Reader      *io.PipeReader
+	Reader      io.ReadCloser
 	Writer      *io.PipeWriter
 	ReadyCh     chan struct{}
 	Once        sync.Once