signRequest method
Implementation
void signRequest(HttpRequest req, String bucket, String key) {
req.headers['date'] = httpDateNow();
if (this.secureToken != null) {
req.headers['x-oss-security-token'] = this.secureToken!;
}
final signature = this.make_signature(req, bucket, key);
req.headers['authorization'] = "OSS ${this.accessKey}:${signature}";
}