Different Output After Copying Stream about k4os.compression.lz4 HOT 5 CLOSED

private static byte[] ReadStream(Stream stream, int length, int blockSize = 1024)
{
    byte[] bytes = new byte[length + blockSize];
    int numBytesToRead = length;
    int numBytesRead = 0;
    do
    {
        int n = stream.Read(bytes, numBytesRead, blockSize);
        numBytesRead += n;
        numBytesToRead -= n;
    }
    while (numBytesToRead > 0);

    return bytes;
}

private static void ReadBlocks(Stream decompressionStream, Stream intermediateStream)
{
    byte[] decompressionBytes = ReadStream(decompressionStream, (int)intermediateStream.Length);
    byte[] intermediateBytes = ReadStream(intermediateStream, (int)intermediateStream.Length);

    for (int i = 0; i < decompressionBytes.Length; i++)
    {
        if (decompressionBytes[i] != intermediateBytes[i])
        {
            throw new Exception("Bytes not equal.");
        }
    }
}

private static void ReadTar(LZ4DecoderStream decompressionStream, MemoryStream intermediateStream)
{
    using (var tarStream = new TarInputStream(decompressionStream, Encoding.UTF8))
    using (var intermediateTarStream = new TarInputStream(intermediateStream, Encoding.UTF8))
    {
        TarEntry tarEntry, intermediateTarEntry = null;
        while (true)
        {
            intermediateTarEntry = intermediateTarStream.GetNextEntry();
            tarEntry = tarStream.GetNextEntry();
            if (tarEntry == null || intermediateTarEntry == null)
            {
                if (tarEntry == null && intermediateTarEntry == null)
                {
                    break;
                }
                else 
                {
                    throw new Exception("One stream ended, the other still has data.");
                }
            }

            if (tarEntry.IsDirectory || intermediateTarEntry.IsDirectory)
            {
                if (tarEntry.IsDirectory && intermediateTarEntry.IsDirectory)
                {
                    continue;
                }
                else
                {
                    throw new Exception("One stream found a directory and the other didn't");
                }
            }

            using (var originalEntryContents = new MemoryStream())
            using (var intermediateEntryContents = new MemoryStream())
            {
                tarStream.CopyEntryContents(originalEntryContents);
                intermediateTarStream.CopyEntryContents(intermediateEntryContents);

                ReadByteByByte(originalEntryContents, intermediateEntryContents);
            }

        }
    }
}