Sample with Rx.Observable.using and node-mysql connection pooling

using.js

var source = Rx.Observable.using(
    () => {
        var conn,
            disposable = Rx.Observable.fromNodeCallback(this.pool.getConnection, this.pool)()
                .doOnNext((connection) => {
                    conn = connection
                });

        disposable.dispose = () => {
            if (conn) {
                conn.release();
            }
        };
        return disposable;
    },
    (futureConnection) => {
        return futureConnection
            .selectMany((conn) => {
                //perform some query with the conn object.
            });
    });