How to make TextEditor auto scroll to end when I call TextDocument.Insert and TextEditor without focus?

[GF-Huang]

Note that the TextEditor without focus, because TextDocument.Insert is trigger by Button clicked.

...
<avalonEdit:TextEditor Document="{Binding Document}" />
<Button Command="{Binding AppendLine}" /> <!-- Pseudo code, omitted the definition of the ICommand/DelegateCommand -->
...

class VM {
    public TextDocument  Document { get; } = new();

    public AppendLine() {
        Document.Insert(Document.TextLength, "adsasdfdsf" + Environment.NewLine)
    }
}