Please make BufferedReadStream public

[Tornhoof]

Hi,
I'm currently building a Batch Handler (see https://github.com/aspnet/BasicMiddleware/issues/246) and I need to parse Headers and the Request line from a Multipart request, the parsing itself is basically just copy/paste of the existing Multipart parser part (it already has header support, I just need to add Request Line support, which is trivial). To properly do that I need to (efficiently) read lines from the request. The class ''BufferedReadStream'' in https://github.com/aspnet/HttpAbstractions/blob/master/src/Microsoft.AspNetCore.WebUtilities/BufferedReadStream.cs solves that. It would be great if you could make the class public so I don't need copy it.

[aspnet-hello]

This issue was moved to dotnet/aspnetcore#2691