Merge pull request #3711 from qnnn/fix-generateId

ensure generateId executes on the scheduler thread specified by publishOn

Author: ryanjbaxter

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/route/CompositeRouteDefinitionLocator.java

@@ -65,7 +65,7 @@ public Flux<RouteDefinition> getRouteDefinitions() {
 	}
 
 	protected Mono<String> randomId() {
-		return Mono.fromSupplier(idGenerator::generateId).map(UUID::toString).publishOn(Schedulers.boundedElastic());
+		return Mono.fromSupplier(idGenerator::generateId).publishOn(Schedulers.boundedElastic()).map(UUID::toString);
 	}
 
 }