Static kCTFontCollectionRemoveDuplicatesOption 

pub unsafe static kCTFontCollectionRemoveDuplicatesOption: &'static CFString

Available on crate feature CTFontCollection only.

kCTFontCollectionRemoveDuplicatesOption

Option key to specify filtering of duplicates.

Specify this option key in the options dictionary with a non- zero value to enable automatic filtering of duplicate font descriptors.

See also Apple’s documentation