In the SFTP and e-mail examples, we executed many of the pieces from the Visual Studio solutions as DLLs. NServiceBus hosts these assemblies and with its underlying pipeline will instantiate and execute a specific module. NServiceBus hosts these projects when installing the NServiceBus.Host reference; in turn, it will execute the associated DLL with the NServiceBus.Host.exe executable.

These DLLs are run by the executable NServiceBus.Host.exe. The NServiceBus.Host.exe file is a utility program to not only run NServiceBus host programs in a console program, but also install the DLLs as Windows Services. This executable makes use of the TopShelf framework, and just as TopShelf has code configurations for Windows Services, so does NServiceBus.Host.exe.

Moreover, it is TopShelf capability to run a console program as a console application while debugging, and run it as a Windows service when the program is installed. This is the main reason TopShelf is so popular; otherwise, if...