using System;

using System.IO;

using System.Linq;

using System.Text;

using System.Text.Json;

using System.Text.RegularExpressions;

using Amazon.Lambda.KafkaEvents;

using Amazon.Lambda.Serialization.SystemTextJson;

​

public class Program

{

    public static void Main()

    {

        string json = @"{

  ""eventSource"": ""SelfManagedKafka"",

  ""bootstrapServers"": ""pkc-xxdnk.us-east-2.aws.confluent.cloud:9092"",

  ""records"": {

    ""documents-onesite-delivery-status-5"": [

      {

        ""topic"": ""documents-onesite-delivery-status"",

        ""partition"": 5,

        ""offset"": 2773,

        ""timestamp"": 1725410562118,

        ""timestampType"": ""CREATE_TIME"",

        ""key"": ""AAABiaeigZIErIGSBIAGxgy0BEgwYzkyMzFhYy1iMmI5LTRkZDAtYWQxZC1iZjFhNmQ3NWIwYzg\\u003d"",

        ""value"": ""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\\u003d"",

        ""headers"": []

      }

    ]

  }

}";

        var serializer = new DefaultLambdaJsonSerializer(options => new JsonSerializerOptions { PropertyNameCaseInsensitive = true });

        var bytes = Encoding.UTF8.GetBytes(Regex.Unescape(json));

        using var stream = new MemoryStream(bytes);

        var kafkaEvent = serializer.Deserialize<KafkaEvent>(stream);

​

        Console.WriteLine(kafkaEvent.Records.First().Value.First().Key);

    }

}

​