title: Akka Actor preStart() & postStop() methods behaviors?
body: <p>Says if I have an Actor for database accessing, an Actor is a singleton instance to handle all clients, or multiple instances for multiple clients? The Actor <code>preStart()</code> and <code>postStop()</code> methods are called only once for all instances? Or will be called when each new Actor instance is created? Is it good to put database initialisation code inside <code>preStart()</code>, and connection returning code inside <code>postStop()</code>?</p>
  
  <p>Thanks</p>