Postgres Stop function not implemented causing the backend to never close the database connection

[jeanmartins]

Function not implemented:
// Stop implements backend.Backend func (*postgresBackend) Stop(context.Context) error { return nil }

Link to the file: https://github.com/microsoft/durabletask-go/blob/a1e5ef044314e2097fa59faf43c50352dc6ed6df/backend/postgres/postgres.go#L996C1-L999C2

[mrjmarcelo]

Hi, @jeanmartins , fixture waiting for pull request approval:

#114

Thanks.