Fixed an issue where the request headers for the content part of the request wouldn't be captured.
For example, sending a request like this:
var stringContent = new StringContent("Hello");
stringContent.Headers.Expires = DateTimeOffset.UtcNow;
var request = new HttpRequestMessage(HttpMethod.Get, "/api/info")
{
Content = stringContent
}would mean that on the captured request the Expires header wasn't present.
Now, all headers from the request.Content.Headers will be captured.
The headers from the request itself were already captured.