nil access when call maped proc

[bung87]

compile with nim c -r .\src\webview2.nim it reports C:\Users\crc32\.nimble\pkgs\memlib-1.2.0\memlib.nim(1029) CreateCoreWebView2EnvironmentWithOptions this may not related to this lib, but I have no clue , so asking here. https://github.com/bung87/webview2/blob/ed77f39687603bb3723d4ff0450990b8bd86e208/src/webview2/browser.nim#L59