Deserialize Problem

[Tom-Plants]

Title:
Unexpected Behavior When Serializing and Deserializing PppoePkt

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Description:
Hi, I encountered an unexpected behavior when serializing and deserializing the ppproperly::pppoe::PppoePkt struct. After deserialization, the PADI field is empty, even though I originally added two tags.

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Reproduction Steps:

Here is a minimal code snippet to reproduce the issue:

let pkt = ppproperly::pppoe::PppoePkt::new_padi(
    iface_mac,
    vec![
        ppproperly::pppoe::PppoeTag {
            data: ppproperly::pppoe::PppoeVal::HostUniq("aaaaaaa".as_bytes().to_vec()),
        },
        ppproperly::pppoe::PppoeTag {
            data: ppproperly::pppoe::PppoeVal::ServiceName("".to_string()),
        },
    ],
);

let mut vec = std::vec::Vec::new();
pkt.serialize(&mut vec)?;

let mut x = ppproperly::pppoe::PppoePkt { ..std::default::Default::default() };
let x1 = vec.as_slice();
let mut x2 = std::io::Cursor::new(x1);
x.deserialize(&mut x2)?;
println!("{}", x);

Expected Behavior:

-- After deserialization, the PADI field inside the PppoePkt struct should contain the two tags I originally added. --

Actual Behavior:

The output is:

PPPoED dst=ff:ff:ff:ff:ff:ff src=0a:f8:b3:20:f9:0d sid=0: PADI []

The tags array inside PADI is empty.

Thanks for your work on this project!