public void init(Logger log, String assemblyName) {
        MappingTrackArchiver archiver = archivers.computeIfAbsent(assemblyName, k -> new MappingTrackArchiver());
        archiver.init(log, assemblyName);
    }
Contains several {@link MappingTrackArchiver} instances, one per assembly
src/main/java/io/fabric8/maven/docker/assembly/TrackArchiverCollection.java