How to add custom header to an Wt:Http:Client request?

Hi,

I'm trying to make a http client request as below by providing a custom header value pair, can anybody let me know how could I get it? Couldn't find it in doc or anywhere. Greatly appreciated.

client_.setFollowRedirect(false);
client_.setMaxRedirects(10);
client_.get("https://google.com")

Best Regards,
Jason Dong