code: func (s *MigrationService) UserMigrationStatus(ctx context.Context, id int64) (*UserMigration, *Response, error) {
  	u := fmt.Sprintf("user/migrations/%v", id)
  
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	// TODO: remove custom Accept header when this API fully launches.
  	req.Header.Set("Accept", mediaTypeMigrationsPreview)
  
  	m := &UserMigration{}
  	resp, err := s.client.Do(ctx, req, m)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return m, resp, nil
  }
docs: // UserMigrationStatus gets the status of a specific migration archive.
  // id is the migration ID.
  //
  // GitHub API docs: https://developer.github.com/v3/migrations/users/#get-the-status-of-a-user-migration