Sorry, I just come In the office, have you figured it out how to use the headers? You just set the properties in the configuration.

config.UserAgentHeader = "myCrawler";

Best regards
Tom

It's  OK.

var Testrequest = await new HttpRequest(
                       new HttpRequestConfig {
                            Url = new Uri("http://httpbin.org/headers"),
                            UserAgentHeader = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:35.0) Gecko/20100101 Firefox/35.0",
                            AwaitProcessing = AwaitProcessingEnum.All
                       });
Console.WriteLine(Testrequest.Response.Json.ToString());

I obtain this result.
{
  "headers": {
    "Accept-Charset": "utf-8,ISO-8859-1;q=0.8,*;q=0.5",
    "Accept-Encoding": "gzip,deflate",
    "Host": "httpbin.org",
    "User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:35.0) Gecko/20100101 Firefox/35.0"
  }
}

Rem :
Tom, Why don't create a Headers property with an initialize list?
So we could add elements like the User Agent
eg : Headers.Add(new KeyValuePair<string, string>("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:35.0) Gecko/20100101 Firefox/35.0")

You can Add() to the headers as you described, you have to initialize the list first:

var config = new HttpRequestConfig { Headers = new List<KeyValuePair<string, string>>() };
config.Headers.Add(new KeyValuePair<string, string>("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:35.0) Gecko/20100101 Firefox/35.0");
...
var request = await new HttpRequest(config);

This avoid the allocation of a empty Headers list when none is needed in the specific context.

P.S.
The style sheet for the code sections in this forms are crap! We must fix this.

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