Complex sentence: In a major departure from Win32 and.NET, most APIs which are expected to take significant time to complete are implemented as asynchronous-the application dispatches the API call, which immediately returns freeing the application to perform other tasks while waiting for the results.
Split into simpler sentences: In a major departure from Win32 and.NET Framework, most APIs which are expected to take significant time to complete are implemented as asynchronous. The application dispatches the API call, which immediately returns freeing the application to perform other tasks while waiting for the results.