ReadAsMultipartAsync equvialent in .NET core 2

See File uploads in ASP.NET Core ... mainly the section of Uploading large files with streaming. It has to be something like

var boundary = MultipartRequestHelper.GetBoundary(
    MediaTypeHeaderValue.Parse(Request.ContentType),
    _defaultFormOptions.MultipartBoundaryLengthLimit);
var reader = new MultipartReader(boundary, HttpContext.Request.Body);

var section = await reader.ReadNextSectionAsync();

Use Microsoft.AspNet.WebApi.Client

You can install https://www.nuget.org/packages/microsoft.aspnet.webapi.client

Then ReadAsMultipartAsync will be available as an extension method in .NET Core 2.

Ref: https://github.com/dotnet/runtime/issues/18848

Sample usage: https://github.com/ringcentral/RingCentral.Net/blob/926f8e33a56f78c20223926a7cef7d4c9ada09b7/RingCentral.Net/BatchOperations.cs#L45