Fixes https://github.com/spring-projects/spring-integration/issues/3367 Introduce a `requestTimeout` and `triggerTimeout` for `BarrierMessageHandler` For instance, if an HTTP request sends a message to the barrier, it should time out after 1min if no trigger message is received. If the trigger message then arrives late and the HTTP request is no longer waiting, it shouldn't wait for 1min before discarding the request but do so immediately.