use std::fmt::Debug;
pub trait ParsableLayer<In> {
    type Out: Sized;
    fn from_bytes(data: In) -> Result<Self::Out, ()>;
}

#[derive(Debug, Clone)]
pub enum SomePacket<'a> {
    UNKNOWN,
    Variant { internal: &'a [u8] },
}

enum SomePacketFamily {}

impl<'a> ParsableLayer<&'a [u8]> for SomePacketFamily {
    type Out = SomePacket<'a>;
    fn from_bytes(data: &'a [u8]) -> Result<SomePacket<'a>, ()>

    {
        let sub = &data[1..];
        Ok(SomePacket::Variant { internal: sub })
    }
}

fn foo<T: for<'a> ParsableLayer<&'a [u8]>>(x: &[u8]) where for<'a> <T as ParsableLayer<&'a [u8]>>::Out: Debug {
    let a =  T::from_bytes(x);
    let b =  T::from_bytes(x);
    println!("{:?} {:?}", a, b);
}

fn main() {
    let x = [1,2,3];
    foo(&x[..]);
}