Avoid intermediate string allocation in Newtonsoft websocket deserialization#677
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…r.DeserializeToWebsocketResponse DeserializeToWebsocketResponse<TResponse>(byte[]) called Encoding.UTF8.GetString(bytes) to materialize the whole websocket payload as a UTF-16 string before handing it to JsonConvert.DeserializeObject. This doubles the memory footprint of every incoming websocket message and is unnecessary: Newtonsoft.Json can read directly from a stream via JsonTextReader, exactly like the sibling DeserializeFromUtf8Stream helper in the same class already does, and like SystemTextJsonSerializer.DeserializeToWebsocketResponse already does by parsing the ReadOnlySpan<byte> directly. This showed up as a measurable allocation hotspot in a production application that processes a high-volume GraphQL subscription over websockets (many messages/sec). Also adds a DeserializeToWebsocketResponseTest to BaseSerializerTest, since DeserializeToWebsocketResponse previously had no direct test coverage (only the Utf8Stream path was tested).
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Summary
JsonTextReaderinstead of first allocating a complete UTF-8 stringJsonConvert.DefaultSettingsby usingJsonSerializer.CreateDefaultValidation
dotnet test tests/GraphQL.Client.Serializer.Tests/GraphQL.Client.Serializer.Tests.csproj -c Release