The IRequestContextHandler type exposes the following members.
Called on the CEF IO thread before a resource request is initiated. This method will not be called if the client associated with browser returns a non-NULL value from GetResourceRequestHandler(IWebBrowser, IBrowser, IFrame, IRequest, Boolean, Boolean, String, Boolean) for the same request (identified by Identifier).
Called on the CEF IO thread before a plugin instance is loaded. The default plugin policy can be set at runtime using the `--plugin-policy=[allow|detect|block]` command-line flag.
Called immediately after the request context has been initialized. It's important to note this event is fired on a CEF UI thread, which by default is not the same as your application UI thread.