If your xUnit parsing takes a long time (don't ask), the entire build agent can be kicked offline, by passing the timeout threshhold on pings (default 4 minutes).
12:39:02 [xUnit] [INFO] - [NUnit-2 (default)] - 110 test report file(s) were found with the pattern '*/TestResult.xml' relative to '/home/builder/jenkins/workspace/foo' for the testing framework 'NUnit-2 (default)'.
12:44:28 [xUnit] [ERROR] - The plugin hasn't been performed correctly: Remote call on JNLP4-connect connection from 22.214.171.124/126.96.36.199:1880 failed
INFO: Ping failed. Terminating the channel JNLP4-connect connection from 188.8.131.52/184.108.40.206:7468.
java.util.concurrent.TimeoutException: Ping started at 1532979041327 hasn't completed by 1532979281327