Function sequence_exact 

pub async fn sequence_exact<I, E>(
    cmds: I,
    env: &mut E,
) -> Result<BoxFuture<'static, ExitStatus>, <I::Item as Spawn<E>>::Error>
where
    I: IntoIterator,
    I::IntoIter: ExactSizeIterator,
    I::Item: Spawn<E>,
    <I::Item as Spawn<E>>::Error: IsFatalError,
    E: ?Sized + LastStatusEnvironment + ReportErrorEnvironment,

Spawns an exact-size iterator of sequential items.

Commands are sequentially executed regardless of the exit status of previous commands. All non-fatal errors are reported and swallowed, however, “fatal” errors are bubbled up and the sequence terminated.