How do threads and replies work between Slack and WhatsApp?

How convly bridges Slack threads and WhatsApp replies in both directions.

Slack and WhatsApp handle threading differently, so convly bridges the two as follows:

If a thread is started in Slack, every message in that thread appears as a reply to the original message on WhatsApp.
If a reply is made on WhatsApp, it appears as a thread in Slack, including any further WhatsApp replies.