We have a self-hosted (i.e. on top of EC2 instance) PostgreSQL instance, which we intent to access from a Step Functions, which invoke multiple Lambdas. I am aware that for the RDS instances there is an RDS Proxy service available which solves for this exact scenario. Given that our instance is self-hosted - is there a way to accomplish caching the database connection across multiple lambda invocations without having to re-establish it for each one?