Error when executing a sample code for Azure Media Service v3

I am following the sample for video uploading using Content-Aware via Azure Media Service SDK v3 in C#. But I am getting an error on the following line of code (https://github.com/Azure-Samples/media-services-v3-dotnet/blob/main/VideoEncoding/Encoding_H264_ContentAware/Program.cs#L266)

var sasUriCollection = asset.GetStorageContainerUrisAsync(
    new MediaAssetStorageContainerSasContent
    {
        Permissions = MediaAssetContainerPermission.ReadWrite,
        ExpireOn = DateTime.UtcNow.AddHours(1)
    });

var sasUri = await sasUriCollection.FirstOrDefaultAsync();

Not sure which library am I missing. Any pointers?

I ended up adding extension method.

public static async Task<T> FirstOrDefaultAsync<T>(this IAsyncEnumerable<T> enumerable)
{
    var enumerator = enumerable.GetAsyncEnumerator();
    await enumerator.MoveNextAsync();
    return enumerator.Current;
}