Tracking external PR #2424

Detailed steps to reproduce the problem?

SetBatchSize does not guard against a nil cs.cursor, which causes a panic if called on a ChangeStream that has not been initialized or has already been closed.
Other methods such as Decode already handle this case explicitly.

Definition of done: what must be done to consider the task complete?

• Added a nil check for cs.cursor in SetBatchSize
• Added a nil cursor test case

The exact Go version used, with patch level:

$ go version

The exact version of the Go driver used:

$ go list -m go.mongodb.org/mongo-driver

Describe how MongoDB is set up. Local vs Hosted, version, topology, load balanced, etc.

The operating system and version (e.g. Windows 7, OSX 10.8, ...)

Security Vulnerabilities

If you’ve identified a security vulnerability in a driver or any other MongoDB project, please report it according to the instructions here