PR https://github.com/dotnet/corefx/pull/38918 removed `_connection.ExtendWindow(bytesRead);` from the response stream's ReadAsync: https://github.com/dotnet/corefx/blob/c14b80faff694bae4e085bad221e2e83410e5f33/src/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http2Stream.cs#L649-L652 but didn't remove it from Read: https://github.com/dotnet/corefx/blob/c14b80faff694bae4e085bad221e2e83410e5f33/src/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http2Stream.cs#L624-L628 I assume that's a bug that needs to be fixed in Read by removing the corresponding line? cc: @geoffkizer