Function verify_after_first_navigation 

pub fn verify_after_first_navigation<R: Runtime>(
    app: &AppHandle<R>,
) -> Result<(), DevToolsError>

The tripwire once more, the first time a page has finished loading; later calls return Ok without looking. The browser process can write its port file after the webview is ready, which is when verify_not_remote_debuggable first runs.