Function derive_session_id 

pub fn derive_session_id<C: CpaceCiphersuite>(
    ya: &[u8],
    ad_a: &[u8],
    yb: &[u8],
    ad_b: &[u8],
    mode: CpaceMode,
) -> Vec<u8> 

Derive the optional session ID output.

sid_output = H.hash(b"CPaceSidOutput" || transcript)