pub fn write_u24be(dst: &mut [u8], val: u32) -> ByteIOResult<()> {
if dst.len() < 3 { return Err(ByteIOError::WriteError); }
dst[0] = (val >> 16) as u8;
pub fn write_u24be(dst: &mut [u8], val: u32) -> ByteIOResult<()> {
if dst.len() < 3 { return Err(ByteIOError::WriteError); }
dst[0] = (val >> 16) as u8;