src/vs/workbench/contrib/timeline/browser/timelinePane.ts/TimelinePane/clear
class TimelinePane:	private clear(cancelPending: boolean) {
		this._visibleItemCount = 0;
		this._maxItemCount = this.pageSize;
		this.timelinesBySource.clear();

		if (cancelPending) {
			for (const { tokenSource } of this.pendingRequests.values()) {
				tokenSource.dispose(true);
			}

			this.pendingRequests.clear();

			if (!this.isBodyVisible()) {
				this.tree.setChildren(null, undefined);
				this._isEmpty = true;
			}
		}
	}