public StrongHWNDSubclass(StrongHWND strongHwnd)
: base(new HWND(strongHwnd.DangerousGetHandle()))
{
// Note that we passed a new "weak" HWND handle to the base class.
// This is because we don't want the StrongHWNDSubclass processing
// a partially disposed handle in its own Dispose methods.
_strongHwnd = strongHwnd;
}