Thank you very much for your answers. The basic requirement was to attach a zip file to email with some details when RFQ is sent to vendors.
the RFQ by standard is created in temp folder and attached to email, we are using the same folder to put the additional zip file attachment and attach this in the email, but we had a performance issue because the same zip file was being created per vendor. I wanted to customize this to generate a zip file in temp folder only once and use this for all vendors in the RFQ case.