[xray] Implement fetch (#2195)

test/stress_tests.py

@@ -492,8 +492,8 @@ class ReconstructionTests(unittest.TestCase):
         # were evicted and whose originating tasks are still running, this
         # for-loop should hang on its first iteration and push an error to the
         # driver.
-        ray.worker.global_worker.local_scheduler_client.reconstruct_object(
-            args[0].id())
+        ray.worker.global_worker.local_scheduler_client.reconstruct_objects(
+            [args[0]], False)
 
         def error_check(errors):
             return len(errors) > 1