if (!src.isEmpty()) {
                List<Plugin> tgt = target.getPlugins();
                Map<Object, Plugin> master = new LinkedHashMap<>(tgt.size() * 2);

                for (Plugin element : tgt) {
                    Object key = getPluginKey().apply(element);
                    master.put(key, element);
                }

                Map<Object, List<Plugin>> predecessors = new LinkedHashMap<>();