var rewrites: MutableList<Rewrite>
If the value of one (or more) of the fields had to be overwritten by the OCN node, it must add this value to the list of rewrites in order to allow the recipient of the message to still be able to validate the original message.
The list contains the replaced fields and their values in the form of a Rewrite object containing the a hash map of previous values, the previous rsv (concatenated signature) and previous signatory.