lback or instantiate a <a href="/api/the-essentials/creating-stores/store/"><code>Store</code></a> whether it&#x27;s loading from previously persisted storage or being run for the first time. Since v5.4.2, this parameter can also be a function that returns the content.</p><p>This method is asynchronous because the persisted data may be on a remote machine or a filesystem. Even for those storage types that are synchronous (like browser storage) it is still recommended that you <code>await</code> calls to thi