RequestHeaders Property

Header Collection - If dealing with headers that only contain a single value then it's easier to use SetHeaderByName(String, String, Boolean) or GetHeaderByName(String). You cannot modify the referrer using headers, use SetReferrer(String, ReferrerPolicy). NOTE: This collection is a copy of the underlying type, to make changes, take a reference to the collection, make your changes, then reassign the collection.

public NameValueCollection Headers { get; set; }

public:
virtual property NameValueCollection^ Headers {
	NameValueCollection^ get () sealed;
	void set (NameValueCollection^ value) sealed;
}

var headers = request.Headers;
var userAgent = headers["User-Agent"];
headers["User-Agent"] = userAgent + " CefSharp";
request.Headers = headers;