boredzo/iso-8601-date-formatter — pull request #11 by mastohhh (2013-05-24 22:03:58+00:00)
Title: Performance problem caused by NSDateFormatter always created

When includeTime property is YES, parameter dateFormat is recreated.

So : dateFormat == lastUsedFormatString is false.

Replacing by [dateFormat isEqualToString:lastUsedFormatString]