The Role of TimerService in ProcessFunction

[Chirag Dewan]

Hi,
Currently, both ProcessFunction and KeyedProcessFunction (and their CoProcess 
counterparts) expose the Context and TimerService in the processElement() 
method. However, if we use the TimerService in non keyed context, it gives a 
runtime error. 
I am a bit confused about these APIs. Is there any specific reason for exposing 
TimerService in non-keyed context especially if it cant be used without keyed 
stream?
Any leads are much appreciated.
Thanks,Chirag