extensions/markdown-language-features/src/util/tableOfContentsWatcher.ts/MdTableOfContentsWatcher/onDidChangeDocument
class MdTableOfContentsWatcher:	private async onDidChangeDocument(document: ITextDocument) {
		if (this.delay > 0) {
			this._pending.set(document.uri);
			this.delayer.trigger(() => this.flushPending());
		} else {
			this.updateForResource(document.uri);
		}
	}