With Mailgun, you'll need to upgrade to a dedicated IP or "managed email service" and pay extra for "better deliverability." At Postmark, great deliverability isn't an up-charge. It's simply included, and we share live delivery data so you can judge for yourself.

There is a similar feature in the standard library Logger class, but the implementation here is safe to use with multiple processes writing to the same log file.

In some cases empty can be the simplest replacement for TCL/expect or other similar programming tools because empty: