code: func CounterSet(marker interface{}, name string, value float64) {
  	if c := getContext(marker); c != nil {
  		// Sets ID so operations can be ordered.
  		c.lock.Lock()
  		c.counters[name] = value
  		c.lock.Unlock()
  		c.emit(&event{
  			Type: eventCounter,
  			Name: name,
  			Args: Args{"value": value},
  			ID:   getID(),
  		})
  	}
  }
docs: // CounterSet registers a new value for a counter.
  //
  // The values will be grouped inside the PID and each name displayed as a
  // separate line.