core/net/
display_buffer.rsuse crate::mem::MaybeUninit;
use crate::{fmt, str};
pub struct DisplayBuffer<const SIZE: usize> {
    buf: [MaybeUninit<u8>; SIZE],
    len: usize,
}
impl<const SIZE: usize> DisplayBuffer<SIZE> {
    #[inline]
    pub const fn new() -> Self {
        Self { buf: [MaybeUninit::uninit(); SIZE], len: 0 }
    }
    #[inline]
    pub fn as_str(&self) -> &str {
        unsafe {
            let s = MaybeUninit::slice_assume_init_ref(&self.buf[..self.len]);
            str::from_utf8_unchecked(s)
        }
    }
}
impl<const SIZE: usize> fmt::Write for DisplayBuffer<SIZE> {
    fn write_str(&mut self, s: &str) -> fmt::Result {
        let bytes = s.as_bytes();
        if let Some(buf) = self.buf.get_mut(self.len..(self.len + bytes.len())) {
            MaybeUninit::copy_from_slice(buf, bytes);
            self.len += bytes.len();
            Ok(())
        } else {
            Err(fmt::Error)
        }
    }
}