I am using a custom tradebar interval as such:

using QuantConnect.Data.Consolidators;

namespace QuantConnect
{
/*
* QuantConnect University: Consolidator Example of Generic Timespan Bars
*/
public class QCUConsolidatorExample : QCAlgorithm
{

TradeBarConsolidator _consolidator;
private const string symbol = "EURUSD";

//Initialize the data and resolution you require for your strategy:
public override void Initialize()
{

//Start and End Date range for the backtest:
SetStartDate(2013, 1, 1);
SetEndDate(DateTime.Now.Date.AddDays(-1));

//Cash allocation
SetCash(25000);

//Add as many securities as you like. All the data will be passed into the event handler:
AddSecurity(SecurityType.Forex, "EURUSD", Resolution.Minute);

//Consolidator Obj:
_consolidator = new TradeBarConsolidator( TimeSpan.FromMinutes(30) );
_consolidator.DataConsolidated += EURUSD_30;

SubscriptionManager.AddConsolidator("EURUSD", _consolidator);

//create TEMAs

}

public void EURUSD_30(Object o, TradeBar bar)
{
Log(Time.ToString("u") + " Close Price: " + bar.Close);
}

//Data Event Handler: New data arrives here. "TradeBars" type is a dictionary of strings so you can access it by symbol.
public void OnData(TradeBars data)
{
// "TradeBars" object holds many "TradeBar" objects: it is a dictionary indexed by the symbol:
//
// e.g. data["MSFT"] data["GOOG"]


}
}
}

I have read the docs and examples on using indicators, however I never saw anything about using indicators with custom tradebar intervals.

How would I create a simple MA on a custom 30 minute tradebar interval?