src/vs/workbench/contrib/notebook/browser/contrib/viewportCustomMarkdown/viewportCustomMarkdown.ts/NotebookViewportContribution/constructor
class NotebookViewportContribution:	constructor(
		private readonly _notebookEditor: INotebookEditor,
		@INotebookService private readonly _notebookService: INotebookService,
		@IAccessibilityService accessibilityService: IAccessibilityService,
	) {
		super();

		this._warmupViewport = new RunOnceScheduler(() => this._warmupViewportNow(), 200);
		this._register(this._warmupViewport);
		this._register(this._notebookEditor.onDidScroll(() => {
			this._warmupViewport.schedule();
		}));

		if (accessibilityService.isScreenReaderOptimized()) {
			this._warmupDocument = new RunOnceScheduler(() => this._warmupDocumentNow(), 200);
			this._register(this._warmupDocument);
			this._register(this._notebookEditor.onDidChangeModel(() => {
				if (this._notebookEditor.hasModel()) {
					this._warmupDocument?.schedule();
				}
			}));

			if (this._notebookEditor.hasModel()) {
				this._warmupDocument?.schedule();
			}
		}
	}