def find_or_build_and_memoize_details(friendly_model)
      friendly_model_ivar = DetailsDelegator.friendly_model_ivar(friendly_model)
      
      val = instance_variable_get(friendly_model_ivar)
      return val if val.present?
      
      instance_variable_set(friendly_model_ivar,
        friendly_model.
        find_or_build_by_active_record_id(id, friendly_details_build_options(friendly_model)))
    end
def find_or_build_and_memoize_details(friendly_model)
      friendly_model_ivar = DetailsDelegator.friendly_model_ivar(friendly_model)
      
      val = instance_variable_get(friendly_model_ivar)
      return val if val.present?
      
      instance_variable_set(friendly_model_ivar,
        friendly_model.
        find_or_build_by_active_record_id(id, friendly_details_build_options(friendly_model)))
    end
Finds or builds the Friendly instance associated through friendly_model. Result is memoized in an instance variable.
 @see FriendlyAttributes::Base.find_or_build_by_active_record_id
 @see FriendlyAttributes::DetailsDelegator.friendly_model_ivar

 @param [Class] friendly_model FriendlyAttributes::Base subclass