How to use WebView2's C API

[apaly]

Hello,
I would like to use Webview2‘s C API. Thanks to #1124 I have been able to display the browser window. However, I am having a struggle to set AdditionalBrowserArguments for "--enable-features=msWebView2EnableDraggableRegions" (using CreateCoreWebView2EnvironmentWithOptions) even after consulting #3605, #2243 and #286.

Here is a pseudo code of what I did:

ICoreWebView2EnvironmentOptionsVtbl lpVtbl = 
{ 
  QueryInterface, // this was defined
  AddRef, // this was defined
  Release, // this was defined
  .get_AdditionalBrowserArguments = getAdditionalBrowserArguments, // this was defined
  .put_AdditionalBrowserArguments = putAdditionalBrowserArguments  // this was defined
};

ICoreWebView2EnvironmentOptions envOptions = { &lpVtbl };

CreateCoreWebView2EnvironmentWithOptions(NULL, NULL, &envOptions, &environmentCreatedHandler)

This causes access violation. Please note that if I replace &envOptions with null the window opens but obviously without any AdditionalBrowserArguments.

Here are my questions:

1. How can I make this setting in C?
2. It seems WebView2‘ C API are meant to be used in a particular way. How are they supposed to be used - any guidance/documentation will be very appreciated?

Thanks.