title: Add/Update realmObject in RealmList
body: <p>I have a realmList, say studentsList within a realmObject, say class. I want to request a list of students for a given class and update the same within studentList.
  Server returned studentList may contain old as well as new students. So I want my realmList to update information for old students along with addition of new students if any.</p>
  
  <p>What I did is ,</p>
  
  <ol>
  <li>Initiated a loop with size == serverReturnedStudentList.size()</li>
  <li>Created student within loop and added in realm (using realm.copyToRealmOrUpdate(student)) </li>
  <li>Received managed student object from step 2.</li>
  <li>Fetch student List for class X and checked if the studentList contains that managedObject or not.</li>
  <li>If not, added student to studentList else did nothing. </li>
  </ol>
  
  <p>It is working as expected but I know this is not the right approach. If I skip that "contains" check (@step4) and directly add managed object to realmList,  multiple entries starts displaying in realmList.</p>
  
  <p>What would be the best approach to handle this scenario? </p>
  
  <p>Another issue is, I have 'n' number of class and 'x' sections under each class. I am making n.x requests in parallel and when I try to start asyncExecutions n.x times, I got pool size limit exception ( which is obvious) and I can't run this on UI thread as my UI becomes unresponsive for 3-5 seconds(while the loop for each studentList is getting executed with executeTransaction for each student)</p>
  
  <p>Any help/suggestion would be highly appreciated. </p>
  
  <p>Thanks in Advance. Cheers!</p>