parser.rs

// Function signature is simplified a bit
fn bytes_received(self, buf, ..) -> Response<..> {
    match self {
        PacketStart => (PacketLength, Bytes(4), next_timeout())
        PacketLength => {
            let len = buf.read_u32();
            (PacketEnd, Bytes(len), next_timeout())
        }
        Packet => {
            parse_packet(&buf[..]);
            (PacketLength, Bytes(4), next_timeout())
        }
    }
}