AwsUpload/S3Client how do I refresh credentials after multi-part credentials have expired?

Question

I have a multi-part upload, using AWS JS SDK v3, that takes a long time. After one hour the credentials expire. I need to find a way to refresh the credentials to keep the upload going. I can ask my backend for new credentials, I just need to understand where to inject them.

The response I get is:

<?xml version="1.0" encoding="UTF-8"?>
<Error>
    <Code>
        ExpiredToken
    </Code>
    <Message>The provided token has expired.</Message>
    <Token-0>REDACTED</Token-0>
    <RequestId>REDACTED</RequestId>
    <HostId>REDACTED</HostId>
</Error>

The code I'm using looks like this:

import { S3Client } from "@aws-sdk/client-s3";
import { Upload as AwsUpload, Progress } from "@aws-sdk/lib-storage";
import type { AwsCredentialIdentity } from "@aws-sdk/types/dist-types/identity/AwsCredentialIdentity";

// ...


const { accessKeyId, secretAccessKey, sessionToken } = session.uploadCredentials;
const selectedFile: File = //...
const region: string = // ...
const key: string = // ...
const multipartUpload = new AwsUpload({
    client: new S3Client({
        maxAttempts: 10,
        region,
        credentials: async (): Promise<AwsCredentialIdentity> => {
            return {
                accessKeyId,
                secretAccessKey,
                sessionToken,
            };
        },
    }),
    params: { Bucket: session.bucket, Key: key, Body: selectedFile },
});

// Irrelevant, but for completeness:
multipartUpload.on("httpUploadProgress", handleUploadProgress);
multipartUpload.done().then(handleUploadResponse).catch(handleUploadError);

I can't figure out how to configure the SDK to ask me for new credentials, when necessary. Can it be done?