twitter/twitter-text-objc — pull request #20 by nicksnyder (2014-11-12 21:34:07+00:00)
Title: remainingCharacterCount returns signed integer so it can be negative.

Currently, if the tweet length is greater than MaxTweetLength, then remainingCharacterCount will underflow the unsigned integer. It makes sense to be able to return a negative number for remainingCharacterCount.