public T Deserialize()

in csharp/json/src/KafkaJsonDeserializer.cs [43:99]
46 lines of code
10 McCabe index (conditional complexity)

        public T Deserialize(ReadOnlySpan<byte> data, bool isNull, SerializationContext context)
        {
            if (isNull || data == null || data.IsEmpty)
            {
                return default(T);
            }

            if (!context.Headers.TryGetLastBytes("schemaId", out var lastHeader) || lastHeader.Length == 0)
            {
                return default(T);
            }

            var schemaId = UTF8Encoding.UTF8.GetString(lastHeader);
            if (string.IsNullOrEmpty(schemaId))
            {
                return default(T);
            }

            var schemaRegistryData = this.schemaRegistryClient.GetSchema(schemaId).Value;
            if (schemaRegistryData.Properties.Format != SchemaFormat.Json)
            {
                throw new SerializationException(new Error(ErrorCode.Local_ValueDeserialization, $"Schema id {schemaId} is not of json format. the schema is a {schemaRegistryData.Properties.Format} schema."));
            }
            else if (string.IsNullOrEmpty(schemaRegistryData.Definition))
            {
                throw new SerializationException(new Error(ErrorCode.Local_ValueDeserialization, $"Schema id {schemaId} has empty schema."));
            }

            // This implementation is actually based on the old Newtonsoft Json implementation which
            // uses a older json-schema draft version.
            // When we updated to use the latest Newtonsoft package/draft, this implementation will
            // need to change using the new classes.
            using (var stringReader = new StringReader(UTF8Encoding.UTF8.GetString(data)))
            {
                JsonTextReader reader = new JsonTextReader(stringReader);
                try
                {
                    JsonValidatingReader validatingReader = new JsonValidatingReader(reader);
                    validatingReader.Schema = JsonSchema.Parse(schemaRegistryData.Definition);

                    IList<string> messages = new List<string>();
                    validatingReader.ValidationEventHandler += (o, a) => messages.Add(a.Message);

                    T obj = serializer.Deserialize<T>(validatingReader);
                    if (messages.Count > 0)
                    {
                        throw new SerializationException(new Error(ErrorCode.Local_ValueDeserialization, string.Concat(messages)));
                    }

                    return obj;
                }
                finally
                {
                    reader.Close();
                }
            }
        }