src/vs/workbench/api/browser/mainThreadComments.ts/MainThreadCommentController/deleteCommentThread
class MainThreadCommentController:	deleteCommentThread(commentThreadHandle: number) {
		let thread = this.getKnownThread(commentThreadHandle);
		this._threads.delete(commentThreadHandle);

		this._commentService.updateComments(this._uniqueId, {
			added: [],
			removed: [thread],
			changed: []
		});

		thread.dispose();
	}