Javadoc
Returns a String representing the encoding of the given message, if the encoding is
recognized. For example if the given message appears to be encoded using HL7 2.x XML rules
then "XML" would be returned. If the encoding is not recognized then null is returned. That
this method returns a specific encoding does not guarantee that the message is correctly
encoded (e.g. well formed XML) - just that it is not encoded using any other encoding than
the one returned. Returns null if the encoding is not recognized.