code: func RegisterPlugin(name string, factory plugins.Factory) {
  	registeredPluginsMux.Lock()
  	defer registeredPluginsMux.Unlock()
  	registeredPlugins[name] = factory
  }
docs: // RegisterPlugin registers a plugin factory with the runtime
  // package. When the runtime is created, the factories are used to parse
  // plugin configuration and instantiate plugins. If no configuration is
  // provided, plugins are not instantiated. This function is idempotent.