src/vs/workbench/api/browser/mainThreadComments.ts/MainThreadCommentController/createCommentThread
class MainThreadCommentController:	createCommentThread(extensionId: string,
		commentThreadHandle: number,
		threadId: string,
		resource: UriComponents,
		range: IRange | ICellRange,
		isTemplate: boolean
	): languages.CommentThread<IRange | ICellRange> {
		const thread = new MainThreadCommentThread(
			commentThreadHandle,
			this.handle,
			extensionId,
			threadId,
			URI.revive(resource).toString(),
			range,
			true,
			isTemplate
		);

		this._threads.set(commentThreadHandle, thread);

		if (thread.isDocumentCommentThread()) {
			this._commentService.updateComments(this._uniqueId, {
				added: [thread],
				removed: [],
				changed: []
			});
		} else {
			this._commentService.updateNotebookComments(this._uniqueId, {
				added: [thread as MainThreadCommentThread<ICellRange>],
				removed: [],
				changed: []
			});
		}

		return thread;
	}