title: Unsubscribing from events - performance hit?
body: <p>Consider the following code (from a performance report):</p>
  
  <p><img src="https://i.stack.imgur.com/bVok1.png" alt="Performance report"></p>
  
  <p>This is part of a property notificiation listener component. The method <code>OnItemPropertyChanged</code> is a private instance-bound method with the <code>PropertyChangedEventHandler</code> signature. This method is called around 100.000 times and is causing significant delays in the application. </p>
  
  <p>Are there performance considerations related to (un)subscribing events? Is there an explanation to why this would cause such a performance hit?</p>