src/vs/workbench/browser/layoutState.ts/LayoutStateModel/setRuntimeValueAndFire
class LayoutStateModel:	private setRuntimeValueAndFire<T extends StorageKeyType>(key: RuntimeStateKey<T>, value: T): void {
		const previousValue = this.stateCache.get(key.name);
		if (previousValue === value) {
			return;
		}

		this.setRuntimeValue(key, value);
		this._onDidChangeState.fire({ key, value });
	}