code: public AttachVolumeResponse attachVolume(String volumeId, String instanceId) {
          return attachVolume(new AttachVolumeRequest().withVolumeId(volumeId).withInstanceId(instanceId));
      }
docs: Attaching the specified volume to a specified instance.
  
  You can attach the specified volume to a specified instance only
  when the volume is Available and the instance is Running or Stopped ,
  otherwise,it's will get <code>409</code> errorCode.
  
  @param volumeId The id of the volume which will be attached to specified instance.
  @param instanceId The id of the instance which will be attached with a volume.
  @return The response containing the volume-instance attach relation.