clientStateToRestore

The client state persisted from the previous segment, if any. Specifically, this is the NSData provided to the previous segment’s finishWithClientState: method. The client is responsible to restore its client state before writing the current segment. For example, clients such as compositors with a temporal element may need some processing history of previous samples in order to generate an output sample at time N. This will be nil for algorithms that are stateless.

var clientStateToRestore: Data? { get }