Message is an instance of an AnalysisMessage defined by a
schema, whose metaschema is AnalysisMessageWeakSchema. (Names are hard.) Code
should be able to perform validation of arguments as needed by using the
message type information to look at the AnalysisMessageWeakSchema and examine the
list of args at runtime. Developers can also create stronger-typed versions
of GenericAnalysisMessage for well-known and stable message types.</p><table class=message-fields><thead><tr><th>Field</th><th>Type</th><th>Descr