If by &#x27;input&#x2F;output&#x27; sources, you mean computations that will pull or push from an external system such as kafka&#x2F;cassandra, there isn&#x27;t any documentation currently. However we have written connectors to Kafka and Kinesis. You can check out the Scala Kafka Source here [1]. Internally we are working on a high performance Kafka Source in C++ (based on librdkafka). At the moment this source can push records downstream at a rate of &gt; 350K QPS.<p>[1]: <a href="https:&#x2F;&#x2F;github.com&#x2F;concord&#x2F;concord-jvm&#x2F;tree&#x2F;master&#x2F;concord_kafka_consumer" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;concord&#x2F;concord-jvm&#x2F;tree&#x2F;master&#x2F;concord_k...</a>