def init_chunked_upload
      headers = {
        'x-ton-content-type'   => content_type,
        'x-ton-content-length' => @file_size,
        'x-ton-expires'        => DEFAULT_EXPIRE,
        'content-length'       => 0,
        'content-type'         => content_type
      }
      resource = "#{DEFAULT_RESOURCE}#{@bucket}?resumable=true"
      TwitterAds::Request.new(
        @client, :post, resource, domain: DEFAULT_DOMAIN, headers: headers).perform
    end
def init_chunked_upload
      headers = {
        'x-ton-content-type'   => content_type,
        'x-ton-content-length' => @file_size,
        'x-ton-expires'        => DEFAULT_EXPIRE,
        'content-length'       => 0,
        'content-type'         => content_type
      }
      resource = "#{DEFAULT_RESOURCE}#{@bucket}?resumable=true"
      TwitterAds::Request.new(
        @client, :post, resource, domain: DEFAULT_DOMAIN, headers: headers).perform
    end
initialization for a multi-chunk upload