switch meta-function among five types.
Declared in <bslmf_switch.h>
template<
size_t t_SWITCH_SELECTOR,
class t_T0,
class t_T1,
class t_T2,
class t_T3,
class t_T4>
using Switch5 = Switch<t_SWITCH_SELECTOR, t_T0, t_T1, t_T2, t_T3, t_T4>;