Static kCMSampleBufferAttachmentKey_DroppedFrameReason 

pub unsafe static kCMSampleBufferAttachmentKey_DroppedFrameReason: &'static CFString

Available on crate feature CMSampleBuffer only.

Indicates the reason the current video frame was dropped.

Sample buffers with this attachment contain no image or data buffer. They mark a dropped video frame. This attachment identifies the reason for the droppage.

See also Apple’s documentation