Redis support for the bb8 connection pool.

Example

use futures_util::future::join_all;
use bb8_redis::{
    bb8,
    redis::{cmd, AsyncCommands},
    RedisConnectionManager
};

#[tokio::main]
async fn main() {
    let manager = RedisConnectionManager::new("redis://localhost").unwrap();
    let pool = bb8::Pool::builder().build(manager).await.unwrap();

    let mut handles = vec![];

    for _i in 0..10 {
        let pool = pool.clone();

        handles.push(tokio::spawn(async move {
            let mut conn = pool.get().await.unwrap();

            let reply: String = cmd("PING").query_async(&mut *conn).await.unwrap();

            assert_eq!("PONG", reply);
        }));
    }

    join_all(handles).await;
}