code: func (r *Request) SetBody(body interface{}, gzipCompress bool) error {
  	switch b := body.(type) {
  	case string:
  		if gzipCompress {
  			return r.setBodyGzip(b)
  		}
  		return r.setBodyString(b)
  	default:
  		if gzipCompress {
  			return r.setBodyGzip(body)
  		}
  		return r.setBodyJson(body)
  	}
  }
docs: // SetBody encodes the body in the request. You may pass a flag to
  // compress the request via gzip.