preemptive authentication on basic authentication has no effect

[marioja]

I use this code and it has not effect, the first HTTP get does not contain the basic authentication header:

	def result = configure {
		request.uri = url2 
		request.auth.basic username, pw, true
	}.get() {
		response.parser(XML[0]) { config, resp ->
			xml(config, resp).xml
		}

I further checked the code and no code uses the preemptive boolean set in BasicAuth or ThreadSafeAuth.