onLoadStart property Null safety

(void Function?(InAppWebViewController controller, Uri? url)?) onLoadStart
final

Event fired when the WebView starts to load an url.

Official Android API: https://developer.android.com/reference/android/webkit/WebViewClient#onPageStarted(android.webkit.WebView,%20java.lang.String,%20android.graphics.Bitmap)

Official iOS API: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455621-webview

Implementation

final void Function(InAppWebViewController controller, Uri? url)? onLoadStart;