src/vs/workbench/services/workingCopy/common/workingCopyBackupService.ts/WorkingCopyBackupService/hasBackupSync
class WorkingCopyBackupService:	hasBackupSync(identifier: IWorkingCopyIdentifier, versionId?: number, meta?: IWorkingCopyBackupMeta): boolean {
		return this.impl.hasBackupSync(identifier, versionId, meta);
	}