Trying to fetch emails that fall outside an applications sync boundaries or looking to retrieve emails during a period when your webhooks failed.
Once you have a list of messages you can retrieve the individual messages and ingest them.
Objects not synced by Nylas are fetched directly from the provider, there can be a considerable delay in this. You will need to test what limit works within the timeouts of the Nylas API 120 seconds.
If the objects are within the sync boundary and less than 30 days old you can use Delta's