Pops `batch_morlist_size` items from the mor objects queue and run asynchronously
        the _process_mor_objects_queue_async method to fill the Mor cache.

def _process_mor_objects_queue(self, instance):
        """
        Pops `batch_morlist_size` items from the mor objects queue and run asynchronously
        the _process_mor_objects_queue_async method to fill the Mor cache.
        """
        i_key = self._instance_key(instance)
        self.mor_cache.init_instance(i_key)

        if not self.mor_objects_queue.contains(i_key):
            self.log.debug("Objects queue is not initialized yet for instance {}, skipping processing".format(i_key))
            return

        for resource_type in RESOURCE_TYPE_METRICS:
            # Batch size can prevent querying large payloads at once if the environment is too large
            # If batch size is set to 0, process everything at once
            batch_size = self.batch_morlist_size or self.mor_objects_queue.size(i_key, resource_type)
            while self.mor_objects_queue.size(i_key, resource_type):
                mors = []
                for _ in range(batch_size):
                    mor = self.mor_objects_queue.pop(i_key, resource_type)
                    if mor is None:
                        self.log.debug(
                            "No more objects of type '{}' left in the queue".format(ensure_unicode(resource_type))
                        )
                        break

                    mor_name = str(mor['mor'])
                    mor['interval'] = REAL_TIME_INTERVAL if mor['mor_type'] in REALTIME_RESOURCES else None
                    # Always update the cache to account for Mors that might have changed parent
                    # in the meantime (e.g. a migrated VM).
                    self.mor_cache.set_mor(i_key, mor_name, mor)

                    # Only do this for non real-time resources i.e. datacenter, datastore and cluster
                    # For hosts and VMs, we can rely on a precomputed list of metrics
                    realtime_only = is_affirmative(instance.get("collect_realtime_only", True))
                    if mor["mor_type"] not in REALTIME_RESOURCES and not realtime_only:
                        mors.append(mor)

                # We will actually schedule jobs for non realtime resources only.
                if mors:
                    self.pool.apply_async(self._process_mor_objects_queue_async, args=(instance, mors))