mongoc_client_kill_cursor doesn't accept a "hint" that would tell the client which server in a replica set or set of mongoses to kill the cursor on, so it's only reliable when connected to a single server.

Beginning with MongoDB 3.2 we begin migrating from the OP_KILLCURSORS message to the killCursors command (DRIVERS-211), which requires the cursor's original database and collection name as well as its id. Again, mongoc_client_kill_cursor doesn't accept these parameters.

Deprecate mongoc_client_kill_cursor since it doesn't work with compound server topologies and will eventually stop working with modern wire protocols. We could replace it with an extended API but it's unnecessary: mongoc_cursor_destroy can always kill the cursor correctly. There's no need for a separate kill-cursors function.