func Create(url string, h http.Header, c *Config) (io.WriteCloser, error) {
	if c == nil {
		c = DefaultConfig
	}
	return newUploader(url, h, c)
}
func Create(url string, h http.Header, c *Config) (io.WriteCloser, error) {
	if c == nil {
		c = DefaultConfig
	}
	return newUploader(url, h, c)
}
// Create creates an S3 object at url and sends multipart upload requests as
// data is written.
//
// If h is not nil, each of its entries is added to the HTTP request header.
// If c is nil, Create uses DefaultConfig.