code: @CheckReturnValue(when = When.NEVER)
    public boolean isLoggedIn() {
      authLock.readLock().lock();
      try {
        return activeUser != null && activeUser.isLoggedIn();
      } finally {
        authLock.readLock().unlock();
      }
    }
docs: Returns whether or not the client is logged in.
  
  @return whether or not the client is logged in.