UT000139: Exchange already complete occurs with undertow statistics enabled

Issue

• When statistics is enabled on the undertow subsystem, we see the following exception in some cases:

Caused by: java.lang.IllegalStateException: UT000139: Exchange already complete
    at io.undertow.server.HttpServerExchange.addExchangeCompleteListener(HttpServerExchange.java:916)
    at io.undertow.server.handlers.MetricsHandler.handleRequest(MetricsHandler.java:54)
    at io.undertow.servlet.core.MetricsChainHandler.handleRequest(MetricsChainHandler.java:59)
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:274)
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchToPath(ServletInitialHandler.java:209)
    at io.undertow.servlet.spec.RequestDispatcherImpl.forwardImpl(RequestDispatcherImpl.java:221)