Hi.
I'd like to serialize `use fugit::{HertzU32, RateExtU32};`
with `postcard::fixint::le`
However I can't use 
```
    #[serde(with = "postcard::fixint::le")]
    pub resolution: HertzU32,
```

I can use 
```
    #[serde_as(as = "SerHz")]

struct SerHz;

impl serde_with::SerializeAs<HertzU32> for SerHz {
    fn serialize_as<S>(value: &HertzU32, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        return serializer.serialize_u32(value.to_Hz());
    }
}

impl<'de> serde_with::DeserializeAs<'de, HertzU32> for SerHz {
    fn deserialize_as<D>(deserializer: D) -> Result<HertzU32, D::Error>
    where
        D: Deserializer<'de>,
    {
        let val = u32::deserialize(deserializer)?;
        return Ok(val.Hz());
    }
}

```
But it still uses varint.
Any ideas ? James Munns  ?