The postfix plugin reports metrics on the postfix queues.
For each of the active, hold, incoming, maildrop, and deferred queues (http://www.postfix.org/QSHAPE_README.html#queues), it will report the queue length (number of items), size (bytes used by items), and age (age of oldest item in seconds).
### Configuration
```toml
[[inputs.postfix]]
## Postfix queue directory. If not provided, telegraf will try to use