What do you guys think is the most truly indifferent response to rejection after one or two dates?

For example, you have one date with a girl that goes well and she flakes on the second with a message saying " I wish you well and I hope you find someone blah blah". I've always found those types of messages irritating and slightly condescending because they are assuming this is going to ruin my day on some level. How do you convey absolute indifference and give them zero ego validation?

"No worries!" Would be my take but im curious what other guys do.