http.go
func (c *Credentials) SignRequest(req *http.Request) (err error) {
	// s, err := c.SignHeader(req.Method, req.URL.String(), hash)
	// req.Header.Set("Authorization", s)
	// return err

	credentials := &hawk.Credentials{
		ID:   c.ClientID,
		Key:  c.AccessToken,
		Hash: sha256.New,
	}
	reqAuth := hawk.NewRequestAuth(req, credentials, 0)
	reqAuth.Ext, err = getExtHeader(c)
	if err != nil {
		return fmt.Errorf("Internal error: was not able to generate hawk ext header from provided credentials:\n%s\n%s", c, err)
	}
	req.Header.Set("Authorization", reqAuth.RequestHeader())
	return nil
}
func (c *Credentials) SignRequest(req *http.Request) (err error) {
	// s, err := c.SignHeader(req.Method, req.URL.String(), hash)
	// req.Header.Set("Authorization", s)
	// return err

	credentials := &hawk.Credentials{
		ID:   c.ClientID,
		Key:  c.AccessToken,
		Hash: sha256.New,
	}
	reqAuth := hawk.NewRequestAuth(req, credentials, 0)
	reqAuth.Ext, err = getExtHeader(c)
	if err != nil {
		return fmt.Errorf("Internal error: was not able to generate hawk ext header from provided credentials:\n%s\n%s", c, err)
	}
	req.Header.Set("Authorization", reqAuth.RequestHeader())
	return nil
}
// SignRequest will add an Authorization header