How would you fix chatmail/core#1383 without modifying this library?

@dignifiedquire A timeout should measure the time between last byte sent and OK received. It is impossible to achieve this by adding a timeout for the whole send operation. Waiting for server response happens inside the library.

So @link2xt @dignifiedquire which of the options would you say is better? Or something else?

• function to reconfigure the timeout in runtime (@link2xt didn't like this option)
• a functional-style setting .timeout_extra_time_per_mb( ...3 minutes... )

I don't think mapping timeouts to message size belongs in this library. So what I would prefer is something like

• send_with_timeout(msg, Duration::from_secs(5).await which allows specifying for the specific message what timeout to use

send_with_timeout looks good to me, not storing the timeout inside the library is nice.

Here is the list of timeouts: https://tools.ietf.org/html/rfc5321#section-4.5.3.2

We are interested in DATA Termination timeout here.