title: How to detect text view begin editing and end editing in swift 3
body: <p>I found related questions and answers in objective-c but I couldn't find a proper way to this with swift? Is there methods to detect for text view same as text filed in swift? </p>
  
  <p>I want to solve the issue hiding text view by keyboard. For that I need a way to detect start and end edit text view. </p>
  
  <p>Any help would be appreciated. 
  Note: I'm using swift 3. </p>