extensions/markdown-language-features/src/preview/preview.ts/MarkdownPreview/scrollTo
class MarkdownPreview:	public scrollTo(topLine: number) {
		if (this._disposed) {
			return;
		}

		if (this._isScrolling) {
			this._isScrolling = false;
			return;
		}

		this._logger.verbose('MarkdownPreview', 'updateForView', { markdownFile: this._resource });
		this._line = topLine;
		this.postMessage({
			type: 'updateView',
			line: topLine,
			source: this._resource.toString()
		});
	}