<PackageReference Include="NETStandard.Library" Version="2.0.0-preview2-25401-01" />

System.Net.Http.Headers.AuthenticationHeaderValue

namespace System.Net.Http.Headers { public class AuthenticationHeaderValue : ICloneable { public string Parameter { get; } public string Scheme { get; } public AuthenticationHeaderValue(string scheme); public AuthenticationHeaderValue(string scheme, string parameter); public static AuthenticationHeaderValue Parse(string input); public static bool TryParse(string input, out AuthenticationHeaderValue parsedValue); } }