xamarinios 
namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
{
    public class HttpRequestHeaders : HttpHeaders
    {
        public StringValues HeaderContentLength { get; set; }
    }
}
.NET 5.06.07.08.09.010.0
.NET Core 2.02.12.23.03.1
.NET Framework 4.6.14.6.24.74.7.14.7.24.84.8.1
.NET Standard 2.02.1
Information specific to xamarinios
Assembly

Microsoft.AspNetCore.Server.Kestrel.Core , Version=2.3.0.0, PublicKeyToken=adb9793829ddae60

Referencing

Your project needs a package reference to Microsoft.AspNetCore.Server.Kestrel.Core.

Package Microsoft.AspNetCore.Server.Kestrel.Core (2.3.0) netstandard2.0
Platform Restrictions

This framework does not have platform annotations.

  • Built-in API
  • Package-provided API