code: func (p pluginHandlerWithMetrics) Validate(a admission.Attributes, o admission.ObjectInterfaces) error {
  	validatingHandler, ok := p.Interface.(admission.ValidationInterface)
  	if !ok {
  		return nil
  	}
  
  	start := time.Now()
  	err := validatingHandler.Validate(a, o)
  	p.observer(time.Since(start), err != nil, a, stepValidate, p.extraLabels...)
  	return err
  }
docs: // Validate performs a non-mutating admission control check and emits metrics.