Function execute_task 

pub fn execute_task<F, G>(
    task_builder: TaskBuilder,
    pre_run: F,
    task_complete: G,
) -> Result<(), Errno>
where
    F: FnOnce(&mut CurrentTask) -> Result<(), Errno> + Send + Sync + 'static,
    G: FnOnce(Result<ExitStatus, Error>) + Send + Sync + 'static,