If you want the Freshchat widget to load async you will need to use the modified code below.

<script>
function initFreshChat() {
    window.fcWidget.init({
      token: "WEB_CHAT_TOKEN",
      host: "WEB_CHAT_HOST"
    });
}

(function(d, id) {
    var fcJS;
    if (d.getElementById(id)) {
        initFreshChat();
        return;
    }
    fcJS = d.createElement('script');
    fcJS.id = id;
    fcJS.async = true;
    fcJS.src = 'https://wchat.freshchat.com/js/widget.js';
    fcJS.onload = initFreshChat;
    d.head.appendChild(fcJS);
}(document, 'freshchat-js-sdk'));
</script>


The above code should be added before the </body> tag of your website's HTML.