code: func (e *Engine) compactHiPriorityLevel(grp CompactionGroup, level compactionLevel, fast bool, wg *sync.WaitGroup) bool {
  	s := e.levelCompactionStrategy(grp, fast, level)
  	if s == nil {
  		return false
  	}
  
  	// Try hi priority limiter, otherwise steal a little from the low priority if we can.
  	if e.compactionLimiter.TryTake() {
  		e.compactionTracker.IncActive(level)
  
  		wg.Add(1)
  		go func() {
  			defer wg.Done()
  			defer e.compactionTracker.DecActive(level)
  			defer e.compactionLimiter.Release()
  			s.Apply()
  			// Release the files in the compaction plan
  			e.CompactionPlan.Release([]CompactionGroup{s.group})
  		}()
  		return true
  	}
  
  	// Return the unused plans
  	return false
  }
docs: // compactHiPriorityLevel kicks off compactions using the high priority policy. It returns
  // true if the compaction was started