title: Checking Identity Email token validity
body: <p>I have a .net core application, where i make, after a register, an email token and i send it via email. 
  The idea is, the user can come with that email token in the client app, and i want to check the validity of it (if it expired, if it's the right token associated with the given email).</p>
  
  <p>I tried to find in userManager any method that i can use. What i found is <code>VerifyUserTokenAsync(ApplicationUser user, string tokenProvider, string purpose, string token)</code> but i don't know what to pass in the parameters.</p>
  
  <p>So, can anyone help with the <code>tokenProvider</code> and <code>purpose</code>
  I want to mention that the email token is generated with <code>GenerateEmailConfirmationTokenAsync</code>. I can check the token with <code>ConfirmEmailAsync</code>, if the result isn't succeeded, the token is invalid, but i don't want to set EmailConfirmed to true if the token is valid.</p>