src/Observers/PreLoadAttributeIdObserver.php
protected function process()
    {

        // query whether or not, we've found a new attribute code => means we've found a new EAV attribute
        if ($this->hasBeenProcessed($attributeCode = $this->getValue(ColumnKeys::ATTRIBUTE_CODE))) {
            return;
        }

        // preserve the attribute ID for the EAV attribute with the passed code
        if ($attribute = $this->loadAttributeByEntityTypeIdAndAttributeCode($this->getEntityTypeId(), $attributeCode)) {
            $this->preLoadAttributeId($attribute);
        }
    }
protected function process()
    {

        // query whether or not, we've found a new attribute code => means we've found a new EAV attribute
        if ($this->hasBeenProcessed($attributeCode = $this->getValue(ColumnKeys::ATTRIBUTE_CODE))) {
            return;
        }

        // preserve the attribute ID for the EAV attribute with the passed code
        if ($attribute = $this->loadAttributeByEntityTypeIdAndAttributeCode($this->getEntityTypeId(), $attributeCode)) {
            $this->preLoadAttributeId($attribute);
        }
    }
Process the observer's business logic.

@return array The processed row