StatusCode="Internal", Detail="Failed to deserialize response message." when using System.WebAdapters

[pockets3407]

I'm not sure if this issue is related to the System.WebAdapters project or here.

I have an existing gRPC server and we are looking to migrate a legacy web client using asp.net web forms to blazor. Ideally, I would like to use the same application hosting both gRPC and the blazor web application.
After adding the System.WebAdapters to my DI during startup,

services.AddSystemWebAdapters();

my gRPC clients no longer work and I get the following exception and log messages.
Exception:

Grpc.Core.RpcException: Status(StatusCode="Internal", Detail="Failed to deserialize response message.")
   at Grpc.Net.Client.Internal.HttpClientCallInvoker.BlockingUnaryCall[TRequest,TResponse](Method`2 method, String host, CallOptions options, TRequest request)
   at Grpc.Core.Interceptors.InterceptingCallInvoker.<BlockingUnaryCall>b__3_0[TRequest,TResponse](TRequest req, ClientInterceptorContext`2 ctx)
   at Grpc.Core.ClientBase.ClientBaseConfiguration.ClientBaseConfigurationInterceptor.BlockingUnaryCall[TRequest,TResponse](TRequest request, ClientInterceptorContext`2 context, BlockingUnaryCallContinuation`2 continuation)
   at Grpc.Core.Interceptors.InterceptingCallInvoker.BlockingUnaryCall[TRequest,TResponse](Method`2 method, String host, CallOptions options, TRequest request)
   at GrpcService1.Greeter.GreeterClient.SayHelloUnary(HelloRequest request, CallOptions options)
   at GrpcService1.Greeter.GreeterClient.SayHelloUnary(HelloRequest request, Metadata headers, Nullable`1 deadline, CancellationToken cancellationToken)

Log Messages:

Grpc.Net.Client.Internal.GrpcCall: Debug: Sending message.
Grpc.Net.Client.Internal.GrpcCall: Trace: Serialized 'GrpcService1.HelloRequest' to 7 byte message.
Grpc.Net.Client.Internal.GrpcCall: Trace: Message sent.
Grpc.AspNetCore.Server.ServerCallHandler: Debug: Reading message.
Grpc.AspNetCore.Server.ServerCallHandler: Trace: Deserializing 7 byte message to 'GrpcService1.HelloRequest'.
Grpc.AspNetCore.Server.ServerCallHandler: Trace: Received message.
Grpc.AspNetCore.Server.ServerCallHandler: Debug: Sending message.
Grpc.AspNetCore.Server.ServerCallHandler: Trace: Serialized 'GrpcService1.HelloReply' to 14 byte message.
Grpc.AspNetCore.Server.ServerCallHandler: Trace: Message sent.
Grpc.Net.Client.Internal.GrpcCall: Trace: Response headers received.
Grpc.Net.Client.Internal.GrpcCall: Debug: Reading message.
Grpc.Net.Client.Internal.GrpcCall: Trace: No message returned.
Grpc.Net.Client.Internal.GrpcCall: Debug: Message not returned from unary or client streaming call.
Grpc.Net.Client.Internal.GrpcCall: Information: Call failed with gRPC error status. Status code: 'Internal', Message: 'Failed to deserialize response message.'.
Grpc.Net.Client.Internal.GrpcCall: Debug: Finished gRPC call.

Any help would be appreciated.

[JamesNK]

I'm guessing System.WebAdapters is incorrectly not flushing any remaining data when the response is completed. That causes the message to never be sent to the client.

[twsouthwick]

This can probably be closed here. We are overriding IHttpResponseBodyFeature in the System.Web adapters but we weren't flushing the pipe if it was written to. Fixes in dotnet/systemweb-adapters#485