end-of-event reminder in calendar app

Is there a calendar app that allow users to set end-of-event reminders? Suppose I schedule myself two-hour long programming task, and I want to get reminded throughout the way - 15 mins left, 5 mins left, time's up, 30 mins over, etc.

Also, it would be even better if the app supports voice recognition. For example, I can say "At 9 am, I am going to write Java programs for 2 hours. Remind me when I'm running out of time", and the app will know what entries to add.

After a few years of trying, I have two schemes worked out. This really should be a Google Calander feature (I've tried posting this solution to the Product Forums with no success - the 'add a reply' button doesn't work - suggestions anyone?) While not an app based solution, these are possibly the only ones available, as I've looked repeatedly.

Best solution: basically, create two IFTTT accounts linked to separate Google calendars. One IFTTT trigger on 'any new event on calendar' to send to a Gmail inbox. Then another IFTTT trigger on 'if new email in inbox from search..' to 'quick add a new event' on the second calendar.

The other workaround using RememberTheMilk, though less setup involved, stopped working after a number of tasks filled the RTM inbox (around 20 or so). RTM has a function to update to Gcal, and has an email address to add tasks that can be used by IFTTT similarly to above.

You might find an IFTTT Applet that runs an alarm with snooze, possibly this one: IFTTT: Can you specify a delay for an action? or this: How to make a IFTTT recipe that when triggered chimes an alarm .... I think there are some assistant apps which use voice input to add calendar events.