code: func (G *global_data) SetHeaders(headers map[string]string) *global_data {
  	if G.Req.Headers == nil {
  		G.Req.Headers = make(map[string]string)
  	}
  	for key, value := range headers {
  		G.Req.Headers[key] = value
  	}
  	return G
  }
docs: // Set several Headers for the coming request