internal SolutionEventsListener(IVsSolution solution, VSIXProjectPackage projectPackage)
        {
            Requires.NotNull(solution, nameof(solution));
            Requires.NotNull(projectPackage, nameof(projectPackage));

            this.solution       = solution;
            this.projectPackage = projectPackage;
        }
        internal PackageHelper(VSIXProjectPackage projectPackage)
        {
            Requires.NotNull(projectPackage, nameof(projectPackage));

            ProjectPackage = projectPackage;
        }