code: public static boolean hasListener(String name) {
      Map<String, LogEventListener> listeners = SelenideLogger.listeners.get();
      return listeners != null && listeners.containsKey(name);
    }
docs: If listener with given name is bound (added) to the current thread.
  
  @param name unique name of listener added by method {@link #addListener(String, LogEventListener)}
  @return true iff method {@link #addListener(String, LogEventListener)} with
  corresponding name has been called in current thread.