pub fn begin(&mut self) -> f64 {
        let delta = self.get_delta(self.clock.elapsed());
        self.clock.reset();
        delta
    }
/// signal that execution for this iteration of the loop has started, mainly for the purpose of starting a timer
signal that execution for this iteration of the loop has started, mainly for the purpose of starting a timer
signal that execution for this iteration of the loop has started mainly for the purpose of starting a timer
pub fn begin(&mut self) -> f64 {
        let delta = self.get_delta(self.clock.elapsed());
        self.clock.reset();
        delta
    }
pub fn begin ( & mut self ) -> f64 { let delta = self . get_delta ( self . clock . elapsed ( ) ) ; self . clock . reset ( ) ; delta }
signal that execution for this iteration of the loop has started, mainly for the purpose of starting a timer
signal that execution for this iteration of the loop has started mainly for the purpose of starting a timer
&mut self