Deflate stream not reading

Question

DeflateStream.Read is not working, I'm trying to read from a compressed memory stream but the byte array argument of read remains empty.

        var memoryStream = new MemoryStream();

        var writeStream = new DeflateStream(memoryStream, CompressionLevel.Optimal, true);

        var readStream = new DeflateStream(memoryStream, CompressionMode.Decompress, true);

        var serializedPayloadBytes = Serialize(new Payload { Message = "Payload" });

        var serializedHeaderBytes = Serialize(new PayloadHeader { Length = serializedPayloadBytes.Length });

        var headerSize = serializedHeaderBytes.Length;

        var package = new byte[serializedHeaderBytes.Length + serializedPayloadBytes.Length];

        Buffer.BlockCopy(serializedHeaderBytes, 0, package, 0, serializedHeaderBytes.Length);

        Buffer.BlockCopy(serializedPayloadBytes, 0, package, serializedHeaderBytes.Length, serializedHeaderBytes.Length);

        writeStream.Write(package, 0, package.Length);

        writeStream.Flush();

        writeStream.Close();

        var arr = new byte[serializedHeaderBytes.Length];

        readStream.Read(arr, 0, headerSize);

The arr is always empty (all bytes are zero), the memoryStream.ToArray() has data.

Answer 1

The MemoryStreams Position is at the end of the stream after writing it. You have to set it back to 0 if you want to read from the same stream again after write.

memoryStream.Position = 0;