Add put-unique

beanstalkd now has a "put-unique" command:
netsweng/beanstalkd@89e186c

[earl]

What's the status of put-unique in mainline beanstalkd?

[Doerge]

put-unique is not in mainline beanstalkd, and probably won't get there.
beanstalkd/beanstalkd#180
With +1 year ago since last commit I would assume mainline is dead. kr is still active, but not on beanstalkd.