envelope

// Moving Average Envelopes
// Defaults of "envelope" (see the indicator reference)
let params = HashMap::from([
    ("percent".to_string(), 2.5),
    ("period".to_string(), 20.0),
]);
let mut indicator = build_checked("envelope", &params)?;

for bar in &bars {
    if let Some(output) = indicator.on_bar(bar) {
        // output.value, output.extra[...], indicator.alerts()
    }
}