title: Writing a custom IUserPasswordStore and SignInManager.PasswordSignInAsync in Identity 2.1
body: <p>Building a custom <code>IUserPasswordStore</code> to connect to a legacy system's username/password table. The password is hashed with custom code in the table so I need to write custom code for <code>PasswordSignInAsync</code>.</p>
  
  <p>Do I need to override <code>PasswordSignInAsync</code> or is there a method I can provide that just does the hashing of the password? If I do override the entire <code>PasswordSignInAsync</code> is there sample code somewhere showing me what needs to be done in the method?</p>