When attempting to close an SseEventSource in Open Liberty, I am seeing the following exception:

[3/9/21, 11:30:57:072 CST] 00000047 id=00000000 kernel.launch.internal.MissingDoPrivDetectionSecurityManager W CWWKE0921W: Current Java 2 Security policy reported a potential violation of Java 2 Security Permission. The application needs to have permissions addedPermission:
("java.lang.RuntimePermission" "modifyThread")
Stack:
java.security.AccessControlException: Access denied ("java.lang.RuntimePermission" "modifyThread")java.base/java.security.AccessController.throwACE(AccessController.java:176)
java.base/java.security.AccessController.checkPermissionHelper(AccessController.java:238)
java.base/java.security.AccessController.checkPermission(AccessController.java:385)
java.base/java.lang.SecurityManager.checkPermission(SecurityManager.java:322)
com.ibm.ws.kernel.launch.internal.MissingDoPrivDetectionSecurityManager.checkPermission(MissingDoPrivDetectionSecurityManager.java:45)
java.base/java.util.concurrent.ThreadPoolExecutor.checkShutdownAccess(ThreadPoolExecutor.java:748)
java.base/java.util.concurrent.ThreadPoolExecutor.shutdownNow(ThreadPoolExecutor.java:1405)
java.base/java.util.concurrent.ScheduledThreadPoolExecutor.shutdownNow(ScheduledThreadPoolExecutor.java:870)
java.base/java.util.concurrent.Executors$DelegatedExecutorService.shutdownNow(Executors.java:693)
org.jboss.resteasy.plugins.providers.sse.client.SseEventSourceScheduler.shutdownNow(SseEventSourceScheduler.java:146)
org.jboss.resteasy.plugins.providers.sse.client.SseEventSourceImpl.close(SseEventSourceImpl.java:255)

I've place an attempted fix at https://github.com/resteasy/Resteasy/pull/2689