onProgressChanged property Null safety

(void Function?(InAppWebViewController controller, int progress)?) onProgressChanged
final

Event fired when the current progress of loading a page is changed.

Official Android API: https://developer.android.com/reference/android/webkit/WebChromeClient#onProgressChanged(android.webkit.WebView,%20int)

Implementation

final void Function(InAppWebViewController controller, int progress)?
    onProgressChanged;