@@ -1,7 +1,9 @@

 import abc

 import asyncio

 import concurrent.futures as concurrent

+import functools

 import inspect

+import itertools

 import pickle

 import sys

 import time

@@ -150,9 +152,10 @@ class BaseRunner(metaclass=abc.ABCMeta):

         self._to_retry = {}

         self._tracebacks = {}

-        # Keeping track of index -> point

         self._id_to_point = {}

-        self._i = 0  # some unique index to be associated with each point

+        self._next_id = functools.partial(

+            next, itertools.count()

+        )  # some unique id to be associated with each point

     def _get_max_tasks(self):

         return self._max_tasks or _get_ncores(self.executor)

@@ -172,10 +175,10 @@ class BaseRunner(metaclass=abc.ABCMeta):

     def _ask(self, n):

         points = []

-        for i, index in enumerate(self._to_retry.keys()):

+        for i, _id in enumerate(self._to_retry.keys()):

             if i == n:

                 break

-            point = self._id_to_point[index]

+            point = self._id_to_point[_id]

             if point not in self.pending_points.values():

                 points.append(point)

@@ -249,11 +252,10 @@ class BaseRunner(metaclass=abc.ABCMeta):

             fut.start_time = start_time

             self.pending_points[fut] = x

             try:

-                i = _key_by_value(self._id_to_point, x)  # O(N)

+                _id = _key_by_value(self._id_to_point, x)  # O(N)

             except StopIteration:  # `x` is not a value in `self._id_to_point`

-                self._i += 1

-                i = self._i

-            self._id_to_point[i] = x

+                _id = self._next_id()

+            self._id_to_point[_id] = x

         # Collect and results and add them to the learner

         futures = list(self.pending_points.keys())