Function tls13_handshake_traffic_secret_from_shared_secret 

pub fn tls13_handshake_traffic_secret_from_shared_secret(
    server_hello_transcript: &HandshakeHash,
    client_random: &Random,
    client: bool,
    suite: &SupportedCipherSuite,
    extracted_shared_secret: &Vec<u8>,
) -> Result<(Prk, KeyScheduleHandshake), FnError>

Compute the client/server secret from a raw shared secret This function is used to decrypt knowledges using the secret extracted through the Finished claim