| Class | Description | 
|---|---|
| SparkGroupAlsoByWindowViaWindowSet | 
 An implementation of  
GroupByKeyViaGroupByKeyOnly.GroupAlsoByWindow logic for grouping by windows and controlling
 trigger firings and pane accumulation. | 
| SparkStateInternals<K> | 
 An implementation of  
StateInternals for the SparkRunner. | 
| SparkTimerInternals | 
 An implementation of  
TimerInternals for the SparkRunner. | 
| StateAndTimers | 
 State and Timers wrapper. 
 | 
| StateSpecFunctions | 
 A class containing  
StateSpec mappingFunctions. |