Email Record: Time-of-flight electron scattering from molecular hydrogen: Benchmark cross sections for excitation of the $X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{Σ}}_{g}^{+}→b{\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{Σ}}_{u}^{+}$ transition