run method
Implementation
void run(String id, Map<String, dynamic> params) {
var webView = InAppWebViewWebElement(viewId: id, messenger: _messenger);
var headlessWebView = HeadlessInAppWebViewWebElement(
id: id, messenger: _messenger, webView: webView);
WebPlatformManager.webViews.putIfAbsent(id, () => webView);
HeadlessInAppWebViewManager.webViews.putIfAbsent(id, () => headlessWebView);
prepare(webView, params);
headlessWebView.onWebViewCreated();
webView.makeInitialLoad();
}