Macro bytecodec_try_decode

macro_rules! bytecodec_try_decode {
    ($decoder:expr, $offset:expr, $buf:expr, $eos:expr) => { ... };
    ($decoder:expr, $offset:expr, $buf:expr, $eos:expr, $($track_arg:tt)*) => { ... };
    ($decoder:expr, $offset:expr, $buf:expr, $eos:expr; $($track_arg:tt)*) => { ... };
}

Tries to decode an item from the given buffer.

Conceptually, this macro is expanded to the following expression.

if !$decoder.is_idle() {
    $offset += track!($decoder.decode(&$buf[$offset..], $eos))?;
    if !$decoder.is_idle() {
        return Ok($offset);
    }
}