title: Use Exchange Property in Camel DSL "to"
body: <p>I want to set a property on a Camel Exchange and then use this property when saving the file.  In my camel dsl I have the following:</p>
  
  <pre><code>.process(processorToSetExhangeProperty)  // sets the property &lt;uid&gt; on the exchange
  .to("file:/tmp?fileName=file-" + property("uid") + ".xml")
  </code></pre>
  
  <p>The file is being saved as:</p>
  
  <pre><code>"file-property{uid}.xml" though
  </code></pre>
  
  <p>My processor is as follows:</p>
  
  <pre><code>@Override
  public void process(Exchange exchange) throws Exception {
      UUID uuid = UUID.randomUUID();
      exchange.setProperty("uid", uuid.toString());
      exchange.setOut(exchange.getIn());
  }
  </code></pre>
  
  <p>Any thoughts on what may be going wrong or how I can achieve this?  </p>