MN wrote:

Are there any difference in handling the stream of data when importing from
an outlook folder
compared with using POP3

Outlook is an e-mail client. It does not supported streamed data. Nothing
shows up in Outlook until the entire package of data gets received. Outlook
*downloads* the e-mails.

You don't import from an Outlook folder. You import from a file.

You have a jumbled mess of technical terms in your vocabulary that you are
spewing out without them actually applying to the software you are asking
about.