This week world leaders have been gathering for the U. N. General Assembly, delivering speeches and holding summit meetings and snarling up traffic on the East Side. But for some presidents and prime ministers, the trip to New York has a local dimension too. It’s a way to connect with immigrants from their country who live here and send money home. And immigrant leaders look forward to the chance for face time with the head of state. Unfortunately it doesn’t always work out the way they hoped. WNYC’s Siddhartha Mitter reports.