STR:
 The client should be connecting to a mongo instance such that

 top.SelectServer.Description.WireVersion.Max < 4

Create and execute a query that specifies limit.

Observe that a multiple of batchSize documents are returned, not the value of limit.

 * if limit < batchSize, batchSize is returned

 * if limit >= batchSize, n * batchSize is returned

Notes:
After a lengthy debugging session, we discovered the following. Hopefully it will guide you to a solution.

• BatchCursor.Next() calls  legacyGetMore, which appends batchSize documents to currentBatch.Data
• If limit < batchSize, numToReturn is a negative number. This may or may not be causing problems. Hard for us to tell as outsiders. This should probably be a short circuit condition
• An extra network request is made. This causes more documents to be added to bc.currentBatch.Data. Limit is not being honored, as there is no logic similar to NewLegacyBatchCursor #118-#126 in legacyGetMore.