How to set "Referer" header in Apache Camel route? -

do know how set "referer" header in apache camel dsl? below. doesn't work.

<setheader headername="referer">                 <constant>ttttt</constant>             </setheader> 

please show route because header setting not enough information.

i found similar question header used: how-to-set-http-headers-on-camel-http4-endpoin