api.go
func (api *TelegramBotAPI) GetFile(fileID string) (*FileResponse, error) {
	resp := &FileResponse{}
	_, err := api.c.getQuerystring(getFile, resp, map[string]string{"file_id": fileID})

	if err != nil {
		return nil, err
	}
	err = check(&resp.baseResponse)
	if err != nil {
		return nil, err
	}
	return resp, nil
}
func (api *TelegramBotAPI) GetFile(fileID string) (*FileResponse, error) {
	resp := &FileResponse{}
	_, err := api.c.getQuerystring(getFile, resp, map[string]string{"file_id": fileID})

	if err != nil {
		return nil, err
	}
	err = check(&resp.baseResponse)
	if err != nil {
		return nil, err
	}
	return resp, nil
}
// GetFile returns a FileResponse containing a Path string needed to
// download a file.
// You will have to construct the download link manually like
// https://api.telegram.org/file/bot<token>/<file_path>, where <file_path>
// is taken from the response.