PYTHON-4921 Eliminate unnecessary killCursors command when batchSize == limit

Author: ShaneHarvey

pymongo/message.py

@@ -252,6 +252,10 @@ def _gen_find_command(
         if limit < 0:
             cmd["singleBatch"] = True
     if batch_size:
+        # When limit and batchSize are equal we increase batchSize by 1 to
+        # avoid an unnecessary killCursors.
+        if limit == batch_size:
+            batch_size += 1
         cmd["batchSize"] = batch_size
     if read_concern.level and not (session and session.in_transaction):
         cmd["readConcern"] = read_concern.document