Elements RTL is a cross-platform library of low-level classes and APIs that provide functionality that normally is platform-specific in ways that are platform agnostic. By using Sugar APIs instead of platform-specific APIs, you can make your code more portable between .NET, Cocoa, Java and Island.
Examples of functionality provided by Sugar are generic container classes (such as Lists and Dictionaries), support for reading and writing common data formats (such as XML and JSON), and access to low-level system APIs that are available (but different) on each platform (such as file and network access).
Sugar is Open Source and available on GitHub, but of course ships in the box with Elements. It is supported for all platfroms and their sub-platforms