logstash/logstash — pull request #539 by michaelklishin (2013-07-03 16:25:55+00:00)
Title: Coerce timestamp to DateTime in Logstash::Event#to_s

`#iso8601` is only available on `DateTime` instances.
This leads the agent crash when `--debug` is used because somehow
`@timestamp` key value ends up being a `Time` instance.

When `DateTime` is loaded, both `DateTime` and `Time` provide `#to_dattime` so this solution is safe.