Use async api to preload user, installation, config on SDK initialization.

Author: nlutsenko

Parse/Internal/ParseManager.m

@@ -427,15 +427,18 @@ - (BFTask *)preloadDiskObjectsToMemoryAsync {
  @weakify(self);
  return [BFTask taskFromExecutor:[BFExecutor executorWithDispatchQueue:_preloadQueue] withBlock:^id{
  @strongify(self);
- [PFUser currentUser];
- [PFConfig currentConfig];
+
+ NSArray *tasks = @[
+ [PFUser getCurrentUserInBackground],
+ [PFConfig getCurrentConfigInBackground],
 #if !TARGET_OS_WATCH && !TARGET_OS_TV
- [PFInstallation currentInstallation];
+  [PFInstallation getCurrentInstallationInBackground],
 #endif
- 
- [self eventuallyQueue];
-
- return nil;
+ ];
+ return [[BFTask taskForCompletionOfAllTasks:tasks] continueWithBlock:^id(BFTask *_) {
+ [self eventuallyQueue];
+ return nil;
+ }];
  }];
 }