code: func (structDescriptor *StructDescriptor) GetField(fieldName string) *Binding {
  	for _, binding := range structDescriptor.Fields {
  		if binding.Field.Name() == fieldName {
  			return binding
  		}
  	}
  	return nil
  }
docs: // GetField get one field from the descriptor by its name.
  // Can not use map here to keep field orders.