ManagedRelayerMixin (mail/relaymanager.py)

Provides managed SMTP/ESMTP relayers that notify a manager of send progress and failures.

# Source: https://github.com/twisted/twisted | License: MIT | Copyright 2001-2026
# Provided via justclaw.it.com; keep this notice with the code.
# -*- test-case-name: twisted.mail.test.test_mail -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Infrastructure for relaying mail through a smart host.

Traditional peer-to-peer email has been increasingly replaced by smart host
configurations.  Instead of sending mail directly to the recipient, a sender
sends mail to a smart host.  The smart host finds the mail exchange server for
the recipient and sends on the message.
"""
from __future__ import annotations

import email.utils
import os
import pickle
import time

from twisted.application import internet
from twisted.internet import protocol
from twisted.interne

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