let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&msg.onion_routing_packet.hop_data[..]) };
let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&msg.onion_routing_packet.hop_data[..]) };