msgpack/msgpack-d — pull request #3 by AndrejMitrovic (2012-11-12 22:51:03+00:00)
Title: Add support for void[0] hash value types, aka sets.

The `void[0][Key]` trick is used when you want to use builtin hashes as Set types (hashes with no values). The library needs to specifically handle this, this pull implements this functionality.