Used to define one or more
ServiceDef#getMarkers() marker annotations for a service implementation. This
allows for injection based on the combination of type and marker interface. These marker interfaces should not have
any values. The mere presence of the marker annotation is all that is needed.
When applied to a module class, this sets the default markers for all services within the module. Markers are
additive, so a Marker annotation on the implementation class and/or specified with
ServiceBindingOptions.withMarker(Class[])
will accumulate; a service may have any number of
markers. Generally one or two is enough.