mongoc_collection_copy(3) on Linux
The text af6fc2fc0aa8, as Debian 9 (Stretch) shipped it.
Performs a deep copy of the collection struct and its configuration. Useful if you intend to call mongoc_collection_set_write_concern, mongoc_collection_set_read_prefs, or mongoc_collection_set_read_concern, and want to preserve an unaltered copy of the struct.