Access violation if fetching connections from pool in external_auth mode unless also specifying external_auth in get_with_options

[ahjulstad]

If creating a pool like this:

        let pool = PoolBuilder::new(username, password, connect_string)
            .max_connections(max_connections)
            .pool_type(PoolType::Heterogeneous)
            .external_auth(true)
            .build()
            .context("failed to create Oracle pool")?;

and then subsequently fetching connections from the pool without specifying external_auth in options like this:

            let opts = PoolOptions::new()
   //             .external_auth(true)   // omitting this
                .tag(tag.clone())
                .match_any_tag(true);
            let conn = pool
                .get_with_options(&opts)
                .context("failed to get Oracle connection from pool")?;

one gets STATUS_ACCESS_VIOLATION on windows (and segfaults on Linux) .. (with async , tokio = { version = "1.53.1", features = ["rt-multi-thread", "macros"], calling Oracle through spawn_blocking }

On Windows it would happen on the second retrieval from the pool, making it not really obvious what was wrong.

It could be that this is only something worth mentioning in the documentation.