public override void Initialize(IServiceProvider serviceProvider)
        {
            base.Initialize(serviceProvider);

            ServiceProvider.AddCommandHandler(GuidList.guidGitHubToolbarCmdSet, PkgCmdIDList.pullRequestCommand,
                                              (s, e) => Reload(new ViewWithData {
                Flow = UIControllerFlow.PullRequests, ViewType = UIViewType.PRList
            }).Forget());

            back = ServiceProvider.AddCommandHandler(GuidList.guidGitHubToolbarCmdSet, PkgCmdIDList.backCommand,
                                                     () => !disabled && currentNavItem > 0,
                                                     () => {
                DisableButtons();
                Reload(navStack[--currentNavItem], true).Forget();
            },
                                                     true);

            forward = ServiceProvider.AddCommandHandler(GuidList.guidGitHubToolbarCmdSet, PkgCmdIDList.forwardCommand,
                                                        () => !disabled && currentNavItem < navStack.Count - 1,
                                                        () => {
                DisableButtons();
                Reload(navStack[++currentNavItem], true).Forget();
            },
                                                        true);

            refresh = ServiceProvider.AddCommandHandler(GuidList.guidGitHubToolbarCmdSet, PkgCmdIDList.refreshCommand,
                                                        () => !disabled && navStack.Count > 0,
                                                        () => {
                DisableButtons();
                Reload().Forget();
            },
                                                        true);

            initialized = true;
        }