use oxyroot::RootFile;
fn main() {
    let tree = RootFile::open("o.root").unwrap().get_tree("T").unwrap();
    // read large_file.root's "kin" tree
    let e_beam_iter = tree.branch("v_i").unwrap().as_iter::<f32>().unwrap();
    // this is fine
    let data: Vec<f32> = e_beam_iter.collect(); // this fails
                                                // println!("{:?}", data);
    let sum: f32 = data.iter().sum();
    println!("{}", sum / data.len() as f32);
}