Standard SMTP over tcp
val with_ : (?config:Async_smtp.Client_config.t ‑> ?credentials:Async_smtp.Types.Credentials.t option ‑> log:Async_smtp.Mail_log.t ‑> ?flows:Async_smtp.Mail_log.Flows.t ‑> ?component:Async_smtp.Mail_log.Component.t ‑> Async_smtp.Types.Address.t ‑> f:(t ‑> 'a Async.Deferred.Or_error.t) ‑> 'a Async.Deferred.Or_error.t) Async.Tcp.with_connect_options