constexpr void* address() const noexcept;
Returns the underlying address of the
coroutine_handle. The return value is non-null if and only if the current value of the
coroutine_handle is obtained from a promise object of a coroutine.
 Return value
The underlying address.
The return value is non-null for specialization std::noop_coroutine_handle, because a
std::noop_coroutine_handle cannot be created without referring to a no-op coroutine.
 See also
| imports a coroutine from a pointer |
(public static member function)