edge-mdns::io::Mdns rand type

[Georges760]

Currently:

pub struct Mdns<'a, M, R, S, RB, SB>
where
    M: RawMutex,
{
    ipv4_interface: Option<Ipv4Addr>,
    ipv6_interface: Option<u32>,
    recv: Mutex<M, R>,
    send: Mutex<M, S>,
    recv_buf: RB,
    send_buf: SB,
    rand: fn(&mut [u8]),
    broadcast_signal: &'a Signal<M, ()>,
    wait_readable: bool,
}

why not having rand being a generic type that implement rand::RngCore ?

Something like:

pub struct Mdns<'a, M, R, S, RB, SB, RNG>
where
    M: RawMutex,
    RNG: rand::RngCore,
{
    ipv4_interface: Option<Ipv4Addr>,
    ipv6_interface: Option<u32>,
    recv: Mutex<M, R>,
    send: Mutex<M, S>,
    recv_buf: RB,
    send_buf: SB,
    rand: RNG,
    broadcast_signal: &'a Signal<M, ()>,
    wait_readable: bool,
}

because having this fonction prototype implies that the Random Number Generator need to be static and use within the fn without being passed as parameter.

[ivmarkov]

Sorry for the delay.

Sure - if you want to PR this, I will merge. The mDNS thing already is heavily generified, so one more generic param is I guess not the end of the world.

For the MCUs I've tested with (rp2040 and the Espressif line), it is not really a problem to put a rand impl in a static context and then wrap it with a fn(&mut [u8]) but you are right that in the context of mDNS it is better to model this with a generic.