Custom NWProtocolFramerImplementation with handshake

Hi, I want to write a custom NWProtocolFramerImplementation with a handshake. In the WWDC 2019 session 713 video, it is specified that the start(framer:) method must return a .willMarkReady and we must call markReady() later. Would it be possible to have an example?

thanks

Custom NWProtocolFramerImplementation with handshake
 
 
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