MongoAsyncDriverPromise.java

@Override
	public F.Promise<Usuario> findById(String id) {
		F.RedeemablePromise<Usuario> promise = F.RedeemablePromise.empty();
		System.out.println("querying...");
		usuarios.
		usuarios.find( eq("_id", id) ).first( (u, e) -> { // FIXME: Single field query
			System.out.println("dispatching callback...");
			if(u == null || e != null){
				promise.failure( new Throwable("no user"));
			} else {
				promise.success(u);
			}
			
		}); //first( (user, t) -> Promise.pure(user) ); // map( (user, t) -> user ); //first( (res, t) -> res );
		System.out.println("derefing completion");
		return promise;

	}