Macro match_message

macro_rules! match_message {
    ($buf:expr, $messages:ty {
        $(( $i1:path $(as $i2:ident )?) $(if $cond:expr)? => $impl:block,)*
        $unknown:ident => $unknown_impl:block $(,)?
    }) => { ... };
}

Perform a match on a message.

use gel_db_protocol::*;
use gel_db_protocol::test_protocol::*;

let buf = [b'?', 0, 0, 0, 4];
match_message!(Message::new(&buf), Backend {
    (DataRow as data) => {
        todo!();
    },
    unknown => {
        eprintln!("Unknown message: {unknown:?}");
    }
});