I find har gau (and the other "crystal" dumplings nasty if I take them on board. Same with cheong fan and nian gao. When they get cold and a bit dried out that the skin/wrapper gets hard and disgusting. And you can't heat them up. Siu mai tends to fare a little better, but still not great cold. I am planning char siu (half fat, never lean) to try. I suggested a friend try a chicken shawarma wrap but warned them the pita might become hard. Waiting for them to come back to advise.

And yes, ziplock bags are your friend.