A producer may choose to write records as part of a transaction, which indicate that the records should remain invisible to consumers until the transaction is committed. However, the consumer client can control how to read such records through the consumer builder isolation level property. Possible values are read_committed or read_uncommitted.

read_committed is the default and tells the client to only request records from a topic where the producer has committed the transaction.

read_uncommitted allow the consumer to request records from topics where the producer of the record has started a transaction and sent records to the broker, but has not completed the transaction. read_uncommitted includes transactional records which have been aborted.

You can either use the SetConsumerOption() method to set the "isolation.level" property, or use the strongly typed method, SetIsolationLevel():
SetConsumerOption("isolation.level", "read_uncommitted").
// or
SetIsolationLevel(IsolationLevel:ReadUncommitted).