getBucket method
Implementation
Future<BucketContents> getBucket(String bucket,
    {String? region,
    String? prefix,
    String? delimiter,
    String? encodingType,
    String? marker,
    int? maxKeys,
    SessionQCloudCredentials? sessionCredentials}) {
  return cosApi.getBucket(serviceKey, bucket, region, prefix, delimiter,
      encodingType, marker, maxKeys, sessionCredentials);
}