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).

Agent:

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 1.1.1.1/1.1.1.1:1880 failed

Server:

INFO: Ping failed. Terminating the channel JNLP4-connect connection from 1.1.1.1/1.1.1.1:7468.
java.util.concurrent.TimeoutException: Ping started at 1532979041327 hasn't completed by 1532979281327
at hudson.remoting.PingThread.ping(PingThread.java:134)
at hudson.remoting.PingThread.run(PingThread.java:90)