I&#x27;m just guessing based on my experience with Amazon&#x27;s Kinesis Client Library (<a href="http:&#x2F;&#x2F;docs.aws.amazon.com&#x2F;kinesis&#x2F;latest&#x2F;dev&#x2F;developing-consumers-with-kcl.html" rel="nofollow">http:&#x2F;&#x2F;docs.aws.amazon.com&#x2F;kinesis&#x2F;latest&#x2F;dev&#x2F;developing-con...</a>), but it probably means that you write something as a package with certain public methods, and they have a wrapper around it that knows how to invoke it. That&#x27;s how KCL integrates with the languages that it supports.