Returns a new state with the runnable scheduled for execution.
      
    
      
      
    
      
      
    
      
      
    
      
    
      
    
      
    
      
    
      
      
    
      
      
    
      
      
    
      Returns a new state with a scheduled task included.
      
    
      
      
    
      
    
      
    
      
      
    
      
      
    
      
Used internally by TestScheduler, represents the internal state used for task scheduling and execution.