gistfile1.groovy

        def content = client.get('/test123') { req ->
            //prepare content-type
            req.header('Content-Type', 'text/plain')

            //return a producing stream to send some data along the request
            Streams
                    .just("Hello")
                    .log('client-send')

        }.flatMap { replies ->

            //successful request, listen for replies
            replies
                    .log('client-received')
                    .when(RuntimeException.class) { ex ->
                        System.out.println(ex)
                    }

        }