title: Camel InterceptFrom behavior
body: <p>A route which polls for files has an interceptor written as below. We wanted to know the total time processed. So we logged the startTime in header.
  We observed that the startTime never changes. This code is inside a RouteBuilder::configure method. I then moved the code to a bean and call the bean from the interceptor. Wanted a bit more clarity, reading the camel documenation on the interceptor, I am still not clear, why this does not work</p>
  
  <pre><code> interceptFrom()
                  .setHeader("fileName",
                          regexReplaceAll(simple("${file:onlyname.noext.single}"),
                                  "[^a-zA-z\\d]", ""))
                  .setHeader("startTime", constant(System.currentTimeMillis()))
  </code></pre>