title: How to use HttpClient with multithreaded operation?
body: <p>I've to do an application that performs a Login POST request in a certain host, then navigates some pages, finds and retrieves some data.
  Becase the website resouce is protected by session, so I have to login the website first before I can do some operation such as get or post some data.
  My question is because HttpClient is not thread-safe, how can I create only one HttpClient instance but threads can perform on it safely?
  Remember that the underlying connection must login first before it can be used to operate.</p>