Derive Macro JsonConvertible 

#[derive(JsonConvertible)]

Derive macro that generates impl JsonConvertible for Type {} with compile-time assertions that all inner types implement JsonSafeFields.

Feature gates are handled externally via cfg_attr:

#[cfg_attr(feature = "json-conversion", derive(JsonConvertible))]
#[serde(tag = "$formatVersion")]
pub enum TokenConfiguration {
    #[serde(rename = "0")]
    V0(TokenConfigurationV0),
}