const buffer

gistfile1.txt

struct Buffer<const N: usize> {
    data: [u8; N]
}

impl<const N: usize> Buffer<N> {
    fn new() -> Self {
        Self {
            data: [0; N]
        }
    }
}

impl<const N: usize> Read for Buffer<N> {
    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
        buf.copy_from_slice(&self.data[0..N]);
        Ok(N)
    }
}