title: Send multiple unique emails at one time
body: <p>I'm trying to find a .Net equivalent of the java code in this question:  <a href="https://stackoverflow.com/questions/4334753/how-to-send-multiple-emails-in-one-session">How to send multiple emails in one session?</a> Amazingly, this question hasn't been answered yet on Stack Overflow (or I'm not searching with the right terms.)</p>
  
  <p>I want to be able to connect to my SMTP server (this is a 3rd party server, not under my control) and send up to 500 emails or so at one time.  These emails are requested by our users, and are all unique.  I know I could loop through a list and send them sequentially, or even use threading to spawn multiple processes, but this seems to be wasteful.  I'd be opening a connection, sending one email, then closing the connection.</p>
  
  <p>I've seen it implied that .Net will cache an SMTP connection, kind of like database connection pooling, but I can't find confirmation.  Plus I'd be relying on code that may have unintended side effects for the SMTP that I'm using.</p>
  
  <p>Has anyone done this in .Net?  Did you use a 3rd party component?  Did you instead just manually implement the SMTP RFC?  I really don't want to have to do that.</p>