If this is meant to fix a bug in HTTP::Headers, it would make sense to submit this as a bugfix to HTTP::Headers or at least report the problem directly to the author. But the RT queue for HTTP-Message has no ticket from you or about this issue, so how's the author supposed to hear about it?
This is a misguided module that doesn't even do what it says it does. It only tests if a value is defined and false, not if it is actually numerically equal to 0. Also it's sloppily coded so it will issue a warning if passed undef as an argument.
API for the object accessors is completely inconsistent. This might come from the webservice, but since the Perl side provides an interface, it would be smart for the author to normalize these accessor names to be more Perlish.
If you're going to reinvent the wheel for the Nth time, you could at least document why. There's already plenty of "light" versions of Moose: Mouse, Moo, Mo, etc. Is yours faster, does it use less memory, is it more compatible with Moose.