src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts/BackLayerWebView/createMarkupPreview
class BackLayerWebView:	private async createMarkupPreview(initialization: IMarkupCellInitialization) {
		if (this._disposed) {
			return;
		}

		if (this.markupPreviewMapping.has(initialization.cellId)) {
			console.error('Trying to create markup preview that already exists');
			return;
		}

		this.markupPreviewMapping.set(initialization.cellId, initialization);
		this._sendMessageToWebview({
			type: 'createMarkupCell',
			cell: initialization
		});
	}