Oftentimes, workflows have related records that are crucial to a workflow's completion. For example, say you're running a workflow on sales data, but you also need the client's data. It's possible that Middle has not yet synced the client's data. If that's the case, when the workflow runs it will fail because it doesn't have a synced client record to key into. To keep this from happening, you must construct some logic to check if all needed records are synced before the workflow runs. You are also able to determine a time limit for how long a record will be requeued, while Middle is syncing the missing data, before the record is discarded.