def subscribe(topic, klass, options={}, &callback)
      command = WampRails::Command::Subscribe.new(topic, klass, options, self)
      self._queue_command(command, callback)
    end
def subscribe(topic, klass, options={}, &callback)
      command = WampRails::Command::Subscribe.new(topic, klass, options, self)
      self._queue_command(command, callback)
    end
Performs a WAMP subscribe
 @note This method is blocking if the callback is not nil