code: protected String idForPath(Path pluginPath) {
          for (PluginWrapper plugin : plugins.values()) {
              if (plugin.getPluginPath().equals(pluginPath)) {
                  return plugin.getPluginId();
              }
          }
  
          return null;
      }
docs: Tests for already loaded plugins on given path.
  
  @param pluginPath the path to investigate
  @return id of plugin or null if not loaded