kCFHTTPAuthenticationSchemeBasic
kCFHTTPAuthenticationSchemeDigest
kCFHTTPAuthenticationSchemeKerberos
kCFHTTPAuthenticationSchemeNegotiate
kCFHTTPAuthenticationSchemeNegotiate2
kCFHTTPAuthenticationSchemeNTLM
kCFHTTPAuthenticationSchemeXMobileMeAuthToken
kCFHTTPVersion1_0
kCFHTTPVersion1_1