Convert XmlWriter to Stream / char / byte []

Question

I have an asp.net/C#/Blazor environment, where a button generates an XML with a specific class. With XML Writer, I can make the file, and even can save/download it, but it goes to the server-side (It must to be downloaded on client-side. please, do not argue about it).

I know Blazor implemented some instant download (https://docs.microsoft.com/en-us/aspnet/core/blazor/file-downloads?view=aspnetcore-6.0) and it works perfect with blank/new files, but the problem is, I don't know how to "pass" or convert my previously generated XML with XML Writer method, because Blazor method(s) only allow Stream, char or byte Arrays downloads.

When I tried to convert it, the error

Some of my code is:

    protected async Task CreateXmlFile(int correlativo,string idDocumento, string siglaDocumento, List<DocumentoXML> documentos = null, List<SignersXML> signersXMLs = null,
                                                                                                              List<ContentXMLComplemento> complementos = null,
                                                                                                              List<SignersXMLComplemento> signersComplemento = null)
{
    _xmlWriterSettings = new XmlWriterSettings
        {
            Indent = true,
            Encoding = new UTF8Encoding(false)
        };

    string fullPath= "";
    XmlWriter writer;
    XmlSerializer serializer;

        var documentoIngresoRaiz = new DocumentoIngresoRaiz
            {
                Content_XML = new List<ContentXML>
                {
                    new ContentXML
                    {
                        sve_XML = new List<sveXML>
                        {
                           new sveXML
                           {
                               Documento_XML = documentos
                           }
                        }
                    }
                },
                Signers_XML = signersXMLs
            };

        fullPath = $"{mainPath}Ingreso-{correlativo}.xml";
        var fileName = $"Ingreso-{correlativo}.xml";

        writer = XmlWriter.Create(fullPath, _xmlWriterSettings);
        serializer = new XmlSerializer(typeof(DocumentoIngresoRaiz));
        serializer.Serialize(writer, documentoIngresoRaiz);
        writer.Close(); 

    //I've been trying with these 3 Blazor method lines, to send my xml as stream
    var fileStream = new MemoryStream(writer);
    using var streamRef = new DotNetStreamReference(stream: fileStream);
    await JS.InvokeVoidAsync("downloadFileFromStream", fileName, streamRef);
}

Error CS1503: Argument 1: cannot convert from 'System.Xml.XmlWriter' to 'byte[]'

I've been looking all around StackOverflow and the Internet with no success. I found some similar posts (I want to download XML file in C# which I created using XmlWriter.Create() on user's system) (How to get a Stream from an XMLWriter?), but they couldn't solve my problem. Any help or tip is welcome. Thank you in advance!