MessageBody is a JSON object, it just happends so that RabbitMQ would like it as a ByteArray
Feels better to have an EmptyGelfMessage as a property not a method

OK. So the alternative was to explicitly call it a builder. I just like methods to be actions
Sneaked DotCover in there to get the test code coverage. But I don't want to commit the settings file

BTW. The coverage is really nice :)
Tests for String Formatter

Cause they not only server as coverage but as documentation
Exposing Dictionary formatter specification through tests
So a "Message" key in a dictionary maps to ShortMessage now.