src/vs/workbench/browser/layoutState.ts/LayoutStateModel/saveKeyToStorage
class LayoutStateModel:	private saveKeyToStorage<T extends StorageKeyType>(key: WorkbenchLayoutStateKey<T>): void {
		const value = this.stateCache.get(key.name) as T;
		this.storageService.store(`${LayoutStateModel.STORAGE_PREFIX}${key.name}`, typeof value === 'object' ? JSON.stringify(value) : value, key.scope, key.target);
	}