pdblp: Return `Volume` Data from `event_type`

Question

Is it possible to specify the columns I want to retreive for each event_type?

For example, event_type = TRADE returns [Open, High, Low, Close, Volume, numEvents] but I just want to see [Volume].

I am pulling 30days of 1 minute interval data for 30 tickers, so including these extra columns is slowing down the query.

end = datetime.datetime.now()
delta = end - BDay(30)
start = delta.replace(hour=0, minute=0, second=0)
interval = 1

cl1 = con.bdib('CL1 Comdty', start_datetime=start, 
         end_datetime=end, event_type='TRADE', interval=interval)

Is there anyway to add a fields parameter such as fields = 'Volume'?