Looking at the UDP code in question in brightcove/hot-shots [1]. The createUdpTransport() function creates an object with a send() method that forwards to socket.send(), calling the underlying function with the same host and port argument each time. It seems to me that this code should call socket.connect(args.host, args.port) once instead, and skip the host and port arguments to the send() calls. Presumably this would result in just a single DNS lookup.

Bonus: the createUdpTransport() function also has a DNS cache, which the author of the article could have enabled with just "cacheDns: true". But if the library code used socket.connect(), this internal cache shouldn't be needed either.

1: https://github.com/brightcove/hot-shots/blob/564ac7bfdaaf366...