Handle `InvalidateSession` in `connect_sharded`?

[Artem]

Hi, discord-rs wizard(s)!

I'm using the connect_sharded now because the bot have reached the 2500 limit.

With two shards it works fine!
But if I try to start three or four shards I get the "Expected Ready during handshake" error.

The code looks like this

let total_shards = 3;
for shard_id in 0 .. total_shards {
    std::thread::Builder::new().name (fomat! ("shard " (shard_id) ", dice_thread"))
        .spawn (move || dice::dice_thread (shard_id, total_shards)) .expect ("!spawn");
}

pub fn dice_thread (shard_id: u8, total_shards: u8) {
    ...
    let (mut dc, ready_ev) = bot.connect_sharded (shard_id, total_shards) .expect ("!connect");

And the log is:

DEBUG:discord::connection: Unexpected event: InvalidateSession
thread 'shard 0, dice_thread' panicked at '!connect: Protocol("Expected Ready during handshake")', /buildslave/rust-bui
note: Run with `RUST_BACKTRACE=1` for a backtrace.

I wonder what the InvalidateSession event tells us?

At the very least it might be better to handle it in order to panic with a better error message or something.

[Artem]

zeyla on "Discord API" pointed out that a five-second pause needed between the connections:
"there is a ratelimit of 1 gateway connection per 5 seconds per IP address, but I'd wait 6 or 7 to be safe(edited)"

Adding the pause solved the problem for me.

I will leave the issue open because the error message and/or documetation can be improved.