An extension package participates in dispatch by registering S3 methods for
mizer generics keyed on its marker class (e.g. getEncounter.mizerMR). This
checks the package namespace's own S3 method registry for any method whose
class is the extension name or its sim variant. Because S3 method
registration does not require the S4 marker class to exist, this lets mizer
recognise a dispatching extension before creating its class, so extension
packages no longer have to define the marker class statically. Defining it
statically as contains = "MizerParams" would in fact prevent the package
from being chained with other extensions, since a sealed class cannot be
re-parented into the chain (see defineExtensionClasses()).
providesDispatchMethods(name)TRUE if the loaded namespace name registers S3 methods for class
name or paste0(name, "Sim"), otherwise FALSE.
The extension identifier (its marker class / package name).