void CheckBaseAddress (Uri baseAddress)
{
if (baseAddress == null)
throw new ArgumentNullException ("baseAddress");
if (!baseAddress.IsAbsoluteUri)
throw new ArgumentException ("baseAddress must be an absolute URI.");
if (baseAddress.Scheme == Uri.UriSchemeHttp ||
baseAddress.Scheme == Uri.UriSchemeHttps)
return;
throw new ArgumentException ("baseAddress scheme must be either http or https.");
}