Function get_service_env_config

pub fn get_service_env_config<'a, T, E>(
    key: ServiceConfigKey<'a>,
    env: &'a Env,
    shared_config_sections: Option<&'a EnvConfigSections>,
    validator: impl Fn(&str) -> Result<T, E>,
) -> Result<Option<T>, EnvConfigError<E>>
where
    E: Error + Send + Sync + 'static,

Given a key, access to the environment, and a validator, return a config value if one was set.