code: public void subscribe(String channel, boolean subscribeOnReconnect,
  			OnMessage onMessage) {
  		ChannelSubscription subscribedChannel = subscribedChannels.get(channel);
  		Pair<Boolean, String> subscribeValidation = isSubscribeValid(channel,
  				subscribedChannel);
  
  		if (subscribeValidation != null && subscribeValidation.first) {
  			subscribedChannel = new ChannelSubscription(subscribeOnReconnect,
  					onMessage);
  			subscribedChannel.setSubscribing(true);
  			subscribedChannels.put(channel, subscribedChannel);
  
  			subscribe(channel, subscribeValidation.second, false, "");
  		}
  	}
docs: Subscribe the specified channel in order to receive messages in that
  channel
  
  @param channel
  Channel to be subscribed
  @param subscribeOnReconnect
  Indicates if the channel should be subscribe if the event on
  reconnected is fired
  @param onMessage
  Event handler that will be called when a message will be
  received on the subscribed channel