Callback that is provided by the application to execute a custom tag.
Public Method Summary
Callback is given the Function Name of the macro and a map of named parameters (the map may contain String, Double, Boolean, Integer, Long, Map, or List values).
functionName is the same name by which the Callback was registered.
It's provided as a convenience to allow a single Callback to be registered for multiple
function call tags.
When application code makes a call to push an event to the data layer, that may cause this callback to execute. The callback will execute on the same thread as the push call.