I want to completely populate the HTTP Connection Pool via JavaScript.

for (let i = 0; i < 255; i++) {
            fetch(`http://testurl`, {
                headers: new Headers({'Connection': 'keep-alive'}),
                keepalive: true
            });
        }

I tried this way, but it doesn’t work. What should I do?

i tried

<script>
    async function test() {
        for (let i = 0; i < 255; i++) {
            fetch(`https://httpbin.org/delay/0`, {
                headers: new Headers({'Connection': 'keep-alive'}),
                keepalive: true
            });
        }
    }
    async function exploit() {
        await test();
        fetch(`https://httpbin.org/delay/0`, {
            headers: new Headers({'Connection': 'keep-alive'}),
            keepalive: true
        });
    }
    exploit()
</script>

But, all requests succeed sequentially. I want to fill up the HTTP Connection Pool and cause subsequent requests to fail.