module WebMockHTTPClients

def async_conn_for_stubbed_request(req, request_signature, webmock_response)

already evaluated, mirroring do_get's stubbed branch.
an extra response from the stub sequence. The thread only delivers what the caller
cached under, which makes the thread evaluate the stub registry again and consume
1 second resolution, so a signature built later can differ from the one the response was
Rebuilding calls headers_from_session again, and the session sets a Date header with
The async thread must not go through do_get, which would rebuild the request signature. 
def async_conn_for_stubbed_request(req, request_signature, webmock_response)
  conn = HTTPClient::Connection.new
  conn.async_thread = Thread.new do
    begin
      WebMock::RequestRegistry.instance.requested_signatures.put(request_signature)
      response = build_httpclient_response(webmock_response, true, req.header)
      @request_filter.each do |filter|
        filter.filter_response(req, response)
      end
      conn.push(response)
      WebMock::CallbackRegistry.invoke_callbacks({lib: :httpclient}, request_signature, webmock_response)
    rescue Exception => e
      conn.push e
    end
  end
  conn
end