Static kCMSampleBufferAttachmentKey_TransitionID 

pub unsafe static kCMSampleBufferAttachmentKey_TransitionID: &'static CFString

Available on crate feature CMSampleBuffer only.

Marks a transition from one source of buffers (eg. song) to another

For example, during gapless playback of a list of songs, this attachment marks the first buffer from the next song. If this attachment is on a buffer containing no samples, the first following buffer that contains samples is the buffer that contains the first samples from the next song. The value of this attachment is a CFTypeRef. This transition identifier should be unique within a playlist, so each transition in a playlist is uniquely identifiable. A CFNumberRef counter that increments with each transition is a simple example.

See also Apple’s documentation