sign.go
func (b *Bucket) Sign(req *http.Request) {
	if req.Header == nil {
		req.Header = http.Header{}
	}
	if b.S3.Keys.SecurityToken != "" {
		req.Header.Set("X-Amz-Security-Token", b.S3.Keys.SecurityToken)
	}
	req.Header.Set("User-Agent", "S3Gof3r")
	s := &signer{
		Time:    time.Now(),
		Request: req,
		Region:  b.S3.Region(),
		Keys:    b.S3.Keys,
	}
	s.sign()
}
func (b *Bucket) Sign(req *http.Request) {
	if req.Header == nil {
		req.Header = http.Header{}
	}
	if b.S3.Keys.SecurityToken != "" {
		req.Header.Set("X-Amz-Security-Token", b.S3.Keys.SecurityToken)
	}
	req.Header.Set("User-Agent", "S3Gof3r")
	s := &signer{
		Time:    time.Now(),
		Request: req,
		Region:  b.S3.Region(),
		Keys:    b.S3.Keys,
	}
	s.sign()
}
// Sign signs the http.Request