src/vs/workbench/services/workingCopy/common/workingCopyBackupTracker.ts/WorkingCopyBackupTracker/doDiscardBackup
class WorkingCopyBackupTracker:	private async doDiscardBackup(workingCopyIdentifier: IWorkingCopyIdentifier, cts: CancellationTokenSource) {
		this.logService.trace(`[backup tracker] discarding backup`, workingCopyIdentifier.resource.toString(), workingCopyIdentifier.typeId);

		// Discard backup
		try {
			await this.workingCopyBackupService.discardBackup(workingCopyIdentifier, cts.token);
		} catch (error) {
			this.logService.error(error);
		}

		// Clear disposable unless we got canceled which would
		// indicate another operation has started meanwhile
		if (!cts.token.isCancellationRequested) {
			this.pendingBackupOperations.delete(workingCopyIdentifier);
		}
	}