code: public CompositeProcessEnginePlugin addProcessEnginePlugin(ProcessEnginePlugin plugin, ProcessEnginePlugin... additionalPlugins) {
      return this.addProcessEnginePlugins(toList(plugin, additionalPlugins));
    }
docs: Add one (or more) plugins.
  
  @param plugin first plugin
  @param additionalPlugins additional vararg plugins
  @return self for fluent usage