Using PacketCodec to decode into non-owned struct

[DJDuque]

Maybe what I am asking doesn't make sense, but is there a way to use PacketCodec to decode into a struct that doesn't own, but instead references a slice in the input Packet<'_>?

I am struggling a bit with the lifetimes. The only way I got this to work is like:

struct TcpPacket {
    pub src: SocketAddr,
    pub dst: SocketAddr,
    pub payload: Box<[u8]>,
}

struct Codec;

impl PacketCodec for Codec {
    type Item = TcpPacket;

    fn decode(&mut self, packet: Packet<'_>) -> Self::Item {
        // Use `etherparse` to get the stuff I want.

        TcpPacket {
            src: (src_ip, src_port).into(),
            dst: (dst_ip, dst_port).into(),
            payload: tcp.payload().into(), // payload has same lifetime as Packet. Turn into Boxed slice to get ownership
        }
    }
}

Is there a way to get e.g.:

struct TcpPacket<'a> {
    pub src: SocketAddr,
    pub dst: SocketAddr,
    pub payload: &'a [u8],
}

I can't get the lifetimes to not complain.

The closest I got was:

struct Codec<'a> {
    phantom: PhantomData<&'a ()>,
}

impl<'a> PacketCodec for Codec<'a> {
    type Item = TcpPacket<'a>;

    fn decode(&mut self, packet: Packet<'_>) -> Self::Item {
        // But if I return the slice in payload it complains about lifetimes
        todo!()
    }
}