def unsubscribe_clients(channel, _json_data)
      log_debug "#{self.class} runs 'unsubscribe_clients' method with  #{channel}"
      return if channel.blank?
      unsubscribe_from_channel(channel)
      @server.subscribers[channel] = []
    end
def unsubscribe_clients(channel, _json_data)
      log_debug "#{self.class} runs 'unsubscribe_clients' method with  #{channel}"
      return if channel.blank?
      unsubscribe_from_channel(channel)
      @server.subscribers[channel] = []
    end
the method will unsubscribe all  clients subscribed to a channel by closing the

 @param [String] channel

 @return [void]

 @api public