Change/convert encoding of AcroFieldType.Text

[jeffro59]

After opening PdfDocument, I access form fields by:
foreach (AcroFieldBase f in form.Fields)

Then I verify field is Text: f.FieldType == AcroFieldType.Text
f.ToString() loses a bullet character (utf8 "E2 80 A2") and renders it as \u0080 (PAD)

I tried accessing: f.Dictionary.TryGet(NameToken.V, out IToken vToken)
In debugger, I see vToken has 2 private properties:
Data: the text value string
EncodedWith: Iso88591

8859-1 is single byte encoding and that explains the loss.

Is there a way to open the document preserving the utf8 encoding of the text field?