code: def stream_download(cookie, tokens, path):
      '''下载流媒体文件.
  
      path - 流文件的绝对路径.
      '''
      url = ''.join([
          const.PCS_URL_D,
          'file?method=download',
          '&path=', encoder.encode_uri_component(path),
          '&app_id=250528',
      ])
      req = net.urlopen_without_redirect(url, headers=
              {'Cookie': cookie.header_output()})
      if req:
          return req
      else:
          return Nonf stream_download(cookie, tokens, path):
      '''下载流媒体文件.
  
      path - 流文件的绝对路径.
      '''
      url = ''.join([
          const.PCS_URL_D,
          'file?method=download',
          '&path=', encoder.encode_uri_component(path),
          '&app_id=250528',
      ])
      req = net.urlopen_without_redirect(url, headers=
              {'Cookie': cookie.header_output()})
      if req:
          return req
      else:
          return None
docs: 下载流媒体文件.
  
      path - 流文件的绝对路径.