public static void SecurityProtocol_Roundtrips()
{
var orig = (SecurityProtocolType)0; // SystemDefault.
Assert.Equal(orig, ServicePointManager.SecurityProtocol);
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11;
Assert.Equal(SecurityProtocolType.Tls11, ServicePointManager.SecurityProtocol);
ServicePointManager.SecurityProtocol = orig;
Assert.Equal(orig, ServicePointManager.SecurityProtocol);
}