use serde::{Deserialize, Deserializer}; // 1.0.91

struct Duration;

impl<'de> Deserialize<'de> for Duration {
    fn deserialize<D>(_deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        #[derive(Deserialize)]
        struct Raw {}

        Ok(Duration)
    }
}

fn main() {}