IonDatagram#add(int, IonValue) throws UnsupportedOperationException

[almann]

IonSequence declares #add(int, IonValue) as required by java.util.List:

public void add(int index, IonValue element)

However it's not currently supported for IonDatagram.

Also, the related curried-insertion method isn't supported either:

public ValueFactory add(int index)

Imported from ION-84,IONJAVA-162

[jonwilsdon]

Resolved.