[bug] Exporting using gRPC doesn't work in net48 projects

[AB027PS]

Package

OpenTelemetry.Exporter.OpenTelemetryProtocol

Package Version

Package Name	Version
OpenTelemetry.Exporter.OpenTelemetryProtocol	1.11.0

Runtime Version

net48

Description

I'm not able to export logs/metrics/traces using gRPC in net48 projects .

Steps to Reproduce

using OpenTelemetry.Resources;
using OpenTelemetry.Trace;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleAppFramework
{
    internal class Program
    {
        static void Main(string[] args)
        {
            using (var provider = Sdk
                .CreateTracerProviderBuilder()
                .AddSource("test")
                .SetResourceBuilder(ResourceBuilder
                    .CreateEmpty()
                    .AddService("ConsoleAppFramework"))
                .AddOtlpExporter()
                .Build())
            {
                var source = new ActivitySource("test");

                while (true)
                {
                    using (var activity = source.StartActivity("testing"))
                    {
                        Thread.Sleep(1000);
                    }
                }
            }
        }

    }
}

Expected Result

Traces get successfully exported

Actual Result

An exception is thrown at line 42 here

opentelemetry-dotnet/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/ExportClient/OtlpGrpcExportClient.cs

Lines 35 to 45 in 75d947c

	/// <inheritdoc/>
	public override ExportClientResponse SendExportRequest(byte[] buffer, int contentLength, DateTime deadlineUtc, CancellationToken cancellationToken = default)
	{
	try
	{
	using var httpRequest = this.CreateHttpRequest(buffer, contentLength);
	using var httpResponse = this.SendHttpRequest(httpRequest, cancellationToken);
	httpResponse.EnsureSuccessStatusCode();

The exception message is Only HTTP/1.0 and HTTP/1.1 version requests are currently supported. Parameter name: value

Additional Context

Exporting via HTTP works fine.

[alanwest]

@rajkumar-rangaraj I did some investigation in to .NET Framework support awhile back. I did it in the context of removing the old gRPC library and supporting .NET Framework with the newer Grpc.Net.Client library. There are some notes in the description of this PR #4860.

Now that the dependency for both gRPC libraries have been removed, maybe we can support .NET Framework with the WinHttpHandler? It would require a new dependency only for the .NET Framework build.

[CraigN]

A workaround of rolling back package OpenTelemetry.Exporter.OpenTelemetryProtocol to 1.10.0 resolves the issue whilst continuing to use all other packages on 1.11.0.

[romerod]

Tried the workaround of using WinHttpHandler which supports HTTP/2 results in a System.Net.Http.HttpRequestException with BadRequest 400.
exporterOptions.HttpClientFactory = () => new HttpClient(new WinHttpHandler());

Tried this with aspire as collector:
docker run --rm -it -p 18888:18888 -p 4317:18889 -e DOTNET_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS=true -d --name aspire-dashboard mcr.microsoft.com/dotnet/aspire-dashboard:9.0

I closed #6066 as it's the same bug. Small repro project can be found there.

[rajkumar-rangaraj]

Adding a WinHttpHandler as shown below will work only if an HTTPS URL is used as the endpoint. For example: https://localhost:4317/.

exporterOptions.HttpClientFactory = () => new HttpClient(new WinHttpHandler());

I'm working on further to find the complete fix.