If you’re in Dumbo right now, time to wolf down that sandwich you’re in the middle of and hightail over to Main Street where the Van Leeuwen artisanal ice cream truck (heretofore found in Soho, among other Manhattan places) has graced Brooklyn with its presence. Hurry though: The truck arrived at noon and will only be there until one o’clock! The truck is parked in front of One Main Street.