efficiency

// Kaufman-style leg efficiency ratio
// Defaults of "efficiency" (see the indicator reference)
let params = HashMap::from([
    ("len".to_string(), 14.0),
]);
let mut indicator = build_checked("efficiency", &params)?;

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