||Allows e-mail messages to be properly defined with all necessary variables
||Creates and returns a message_event object, which is used to send direct
and RPC calls via RabbitMQ and other event dispatches used within Apex.
||Creates a EventResponseInterface object, which is used to send back to the
front-end software during a RPC call. This is the response created and
returned by the RPC listeners.
||Defines a SMS message all all properties of it.
||A web socket message interface class.