Support LargeMessage.getData

in certain AMQP Large Messages we may not have the header parsed properly during the initial chunks. And as a result we may incur in a situation where annotations properties are not available on the server.

When the server tries to parse these, it may try to call getData() which will not be supported and throw an exception.

This is to provide an alternative implementation so in case it happens at least the message is parsed without an issue.