SlackBuildsOrg/libraries/libdex

While Dex is using GObject and GIO, it implements it's own fundamental
type (DexObject) for which all other types inherit.
Dex is a library supporting "Deferred Execution" with the explicit 
goal of integrating with GNOME and GTK-based applications.
It provides primatives for supporting futures in a variety of ways 
with both read-only and writable views. Additionally, integration
with existing asynchronous-based APIs is provided through the use of
wrapper promises.