Overview:

I raised DBZ-3331 because we have a very large MongoDB collection that isn't being snapshotted in time of the oplog window. A solution to this problem could be providing a feature to optionally stream data from the oplog concurrently while performing the snapshot. 

I think this feature would be useful for more than just MongoDB. With PostgreSQL it is possible that the disks get filled with WAL files if a snapshot takes too long on a high traffic server. With MySQL there is the same problem as MongoDB that if the snapshot takes longer than the binlog retention period the connector will fail.