There is Santiago's work on TaskIT...https://www.mail-archive.com/pharo-dev@lists.pharo.org/msg17446.html (and you can search for the whole thread in this mailing list ^^)
2014-07-29 1:04 GMT+02:00 Sebastian Sastre <sebastian@flowingconcept.com>:
Do we have Promises and/or Futures for Pharo?A+ ones?