title: What are these characters in mimetype octet-stream?
body: <p>following is my response data I cannot understand what kind of characters are these?</p>
  
  <pre><code>b'l\x00\x00\x00{"fk_bin_data_lib":"FKDATAHS101","user_id":"18","verify_mode":"1","io_mode":"0","io_time":"20190311120940"}\x00'
  </code></pre>