<PackageReference Include="System.Threading.RateLimiting" Version="11.0.0-rc.1.26425.128" />

System.Threading.RateLimiting.MetadataName

public static class MetadataName
Contains some common metadata name-type pairs and helper method to create a metadata name.
namespace System.Threading.RateLimiting { public static class MetadataName { public static MetadataName<TimeSpan> RetryAfter { get; } public static MetadataName<string> ReasonPhrase { get; } public static MetadataName<T> Create<[System.Runtime.CompilerServices.Nullable(2)] T>(string name); } }