SetField doesn't seem to work when write TiffTag.XMLPACKET

[Samachi]

It works well for reading XMLPACKET, but it doesn't work for writing XMLPACKET using SetField.
I figured it out for myself and wrote it in a way that seemed easier:

output.SetField(TiffTag.IMAGEWIDTH, tiff.GetField(TiffTag.XMLPACKET));

But an exception is thrown:
System.InvalidCastException:“Unable to cast object of type 'BitMiracle.LibTiff.Classic.FieldValue[]' to type 'System.IConvertible'.”

Let me write it a different way:

output.SetField(TiffTag.XMLPACKET, new object[] { tiff.GetField(TiffTag.XMLPACKET)[0].Value, tiff.GetField(TiffTag.XMLPACKET)[1].Value});

This time it could run, but it didn't seem to work.

When I checked the source code, the SetField method doesn't seem to have an implementation for XMLPACKET.

Would you tell me how to write XMLPACKET data? Thank you very much.