Speed up display of "delivered" etc. status on outgoing messages

[RichardTaylor]

Currently there can be a delay of a day between a message being sent and the green tick and "delivered" following confirmation from the logs of a delivery status notification from the mailserver belonging to the authority.

Prior to a status becoming available the system shows "Unknown", and explains:

We don't know the delivery status for this message. We couldn't determine the delivery status of this message. It can take up to 24 hours after the message has been sent to determine delivery status information.

This issue follows correspondence from a user who said they waited over 24 hours for the status to update.

[garethrees]

Could be a combination of slow import plus cached page (#1006).

We need to wait for the current day's log to be rotated out of service before we import it. The alternative would be to stream the log in to the app, but that would be a significant undertaking.

[RichardTaylor]

A WhatDoTheyKnow user has written:

in the corner of the reply I thought I was sending is a little Icon saying Unknown instead of a green tick which is shown on my original request. Does this mean that the reply I thought I sent has not been transmitted

[garethrees]

Another issue caused here is that when an initial message fails and then we resend, the status stays in the "Failed" state until we import logs again. This makes it look like the resend has failed for a short period of time.