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.