src/vs/workbench/contrib/comments/browser/commentService.ts/CommentService/getDocumentComments
class CommentService:	async getDocumentComments(resource: URI): Promise<(ICommentInfo | null)[]> {
		const commentControlResult: Promise<ICommentInfo | null>[] = [];

		this._commentControls.forEach(control => {
			commentControlResult.push(control.getDocumentComments(resource, CancellationToken.None)
				.catch(_ => {
					return null;
				}));
		});

		return Promise.all(commentControlResult);
	}