#[derive(Serialize)]
struct Record {
    data: Vec<u8>
}

fn playground() {
    let record = Record {
        data: vec![1,2]
    };
    // data field
    // => encoded as in int array : [4,1,1,1,2,0]
    // => encoded as bytes : [4,1,2]
}   

#[derive(Serialize, Deserialize)]
struct Record {
    #[serde(with = "serde_avro_bytes::bytes")]
    key: Vec<u8>,
    #[serde(with = "serde_avro_bytes::bytes::option")]
    key2: Option<Vec<u8>>,
    #[serde(with = "serde_avro_bytes::hashmap")]
    key3: HashMap<Vec<u8>, Vec<u8>>,
    #[serde(with = "serde_avro_bytes::btreemap::option")]
    key4: Option<BTreeMap<Vec<u8>, Vec<u8>>>,
    #[serde(with = "serde_avro_bytes::list")]
    key5: Vec<Vec<u8>>,
    #[serde(with = "serde_avro_bytes::list::option")]
    key6: Option<Vec<Vec<u8>>>,
}