Function sample::window::hanning

Important traits for Window<F, W>

impl<F, W> Iterator for Window<F, W> where
    F: Frame,
    W: Type,  type Item = F;

pub fn hanning<F>(num_frames: usize) -> Window<F, Hanning> where
    F: Frame, 

A helper function for constructing a Window that uses a Hanning Type function.