prog.cs(3,22): error CS0246: The type or namespace name `IClient' could not be found. Are you missing an assembly reference?
prog.cs(5,22): error CS0246: The type or namespace name `IClient' could not be found. Are you missing an assembly reference?
prog.cs(10,18): error CS0246: The type or namespace name `Task' could not be found. Are you missing `System.Threading.Tasks' using directive?
Compilation failed: 3 error(s), 0 warnings