Hello Kuba,
There is apparently no such feature in preparation, judging by available public documentation and news. It brings little benefit to speculate on possible implementation and approximate dates. Decisions on software development and new features may get overturned at a moment's notice, and issue dates shifted due to unforeseen occurrences and test results.
You may be able to simply set up a workaround, by way of an app in App Engine, and benefit of similar functionality right now. For coding and programming architecture, as well as implementing new Cloud Tasks related functionality, you may be better served in dedicated forums such as stackoverflow, where experienced programmers are within reach and ready to help.