Timeout occurs when setting handled(true) for onException() in a SwitchYard Camel route

Issue

• In a Camel route like the following, when an exception is thrown in the normal route and caught in the onException route, the message won't be replied back to the caller of the Camel service and thus eventually timeout exception happens at a service gateway binding:

  onException(Exception.class)
      .handled(true)
      .transform().simple("ERROR: ${exception.message}");
  
  from("switchyard://ProxyService")
      .handleFault()
      .to("switchyard://ReverseService")
      .transform().simple("OK: ${body}");
  

• Note that this behaviour contradicts the normal behaviour of Camel, in which the following onException clause can send a response back to the caller:

  onException(Exception.class)
      .handled(true)
      .transform().simple("ERROR: ${exception.message}");