Shim to use nom parser with tokio codec.

shim.rs

// Change packet to your parsers result type

/// Shim to use the parser with tokio codec.
pub struct Shim {}

impl Shim {
    pub fn new() -> Proto {
        Proto {}
    }
}

impl Decoder for Shim {
    type Item = Packet;
    type Error = anyhow::Error;
    // Err(e) -> decoding failed
    // Ok(Some(msg)) -> decoding worked
    // Ok(None) -> not enough data
    fn decode(&mut self,src: &mut BytesMut) -> Result<Option<Self::Item>, anyhow::Error> {
        // Change this to your parser 
        match parse_packet(src) {
            Ok((i, msg)) => {
                src.advance(src.len() - i.len());
                Ok(Some(msg))
            },
            Err(e) => {
                use nom::Err as NomErr;
                let e = e.to_owned();
                match e {
                    NomErr::Error(_) => Err(e.into()),
                    NomErr::Failure(_) => Err(e.into()),
                    NomErr::Incomplete(_) => Ok(None)
                }
            },
        }
    }
}