Constructor. If the user has provided an implementation of IStartup in Listen then the functionality
of the provided implementation will be used in place of the default behaviour of ConfigureServices and Configure
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2