Function cmd_config_patch 

pub async fn cmd_config_patch(
    client: &VtaClient,
    label_prefix: &str,
    vta_name: Option<String>,
    public_url: Option<String>,
    rate_limits: RateLimitOverrides,
) -> Result<(), Box<dyn Error>>

cmd_config_update plus the runtime rate-limit keys. Rate-limit values travel as JSON integers.