AddToScoreboard will set the message ID in the section in the scoreboard.

IsInScoreboard will check if the given message ID in the section is present.

MoveToRetryQueue moves a message (back) to retry queue and update retry info.

ProcessMessage will process a message found in the processing queue.

ProcessRetryQueue will process all mails found in the retry queue or removes them when they are expired.

ProcessStuckIncomingMessages will process stuck message found in the incoming queue.

ProcessStuckProcessingMessages will process stuck message found in the processing queue.

QueueIncomingMessage queues message on the uploaded channel so it can be picked up for processing by the main loop.

RemoveFromScoreboard will remove the message ID from the section in the scoreboard.

MaxRetries defines how many retries we can do for sending a message.

IncomingChannel Message with given msgID is incoming from a client.