PrometheusCollector is not thread-safe causing NPEs during deployment

10:33:32,706 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-3) MSC000001: Failed to start service jboss.deployment.subunit."web-sso.ear"."sso-with-no-auth.war".metrics: org.jboss.msc.service.StartException in service jboss.deployment.subunit."web-sso.ear"."sso-with-no-auth.war".metrics: Failed to start service
	at org.jboss.msc.service.ServiceControllerImpl$StartTask.execute(ServiceControllerImpl.java:1730)
	at org.jboss.msc.service.ServiceControllerImpl$ControllerTask.run(ServiceControllerImpl.java:1558)
	at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
	at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1982)
	at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
	at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException
	at org.wildfly.extension.microprofile.metrics.PrometheusCollector.addMetricFamilySampleSupplier(PrometheusCollector.java:32)
	at org.wildfly.extension.microprofile.metrics.MetricCollector.collectResourceMetrics0(MetricCollector.java:157)
	at org.wildfly.extension.microprofile.metrics.MetricCollector.collectResourceMetrics0(MetricCollector.java:166)
	at org.wildfly.extension.microprofile.metrics.MetricCollector.collectResourceMetrics(MetricCollector.java:92)
	at org.wildfly.extension.microprofile.metrics.deployment.DeploymentMetricService.start(DeploymentMetricService.java:54)
	at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1738)
	at org.jboss.msc.service.ServiceControllerImpl$StartTask.execute(ServiceControllerImpl.java:1700)
	... 6 more