protected void logException(Exchange exchange, Throwable throwable) {
   if (tracer.isTraceExceptions()) {
     if (tracer.isLogStackTrace()) {
       logger.process(exchange, throwable);
     } else {
       logger.process(exchange, ", Exception: " + throwable.toString());
     }
   }
 }
 protected void logExchange(Exchange exchange) throws Exception {
   // process the exchange that formats and logs it
   logger.process(exchange);
 }