Function message_decrypt_prekey 

pub async fn message_decrypt_prekey<R: Rng + CryptoRng>(
    ciphertext: &PreKeySignalMessage,
    remote_address: &ProtocolAddress,
    local_address: &ProtocolAddress,
    session_store: &mut dyn SessionStore,
    identity_store: &mut dyn IdentityKeyStore,
    pre_key_store: &mut dyn PreKeyStore,
    signed_pre_key_store: &dyn SignedPreKeyStore,
    kyber_pre_key_store: &mut dyn KyberPreKeyStore,
    csprng: &mut R,
) -> Result<Vec<u8>>

Decrypt a PreKeySignalMessage from remote_address.

Processes the pre-key material to establish a session (via session::process_prekey), then decrypts the inner SignalMessage.