【Unity】文字列をGzip圧縮・展開する

using System.IO;
using Unity.IO.Compression;
public static class GZipUtility
{
    /// <summary>
    /// GZipか確認します。
    /// </ummary>
    public static bool isGZIP(byte[] _header)
    {
        if(_header.IsNullOrEmpty())
        {
            return false;
        }
        byte[] signature =
        {
            GZipConstants.ID1,
            GZipConstants.ID2,
        };
        if(_header[0] != signature[0] || _header[1] != signature[1])
        {
            return false;
        }
        return true;
    }
    /// <summary>
    /// GZIP圧縮したバッファを返します。
    /// </summary>
    public static byte[] ComporessGZIP(string _str)
    {
        using(var memoryStream = new MemoryStream())
        {
            using (var inflateStream = new GZipStream(memoryStream, CompressionMode.Compress))
            {
                using(var writer = new StreamWriter(inflateStream))
                {
                    writer.Write(_str);
                }
            }
            return memoryStream.ToArray();
        }
    }
    /// <summary>
    /// GZIP圧縮されたバッファを解凍します。
    /// </summary>
    public static string DeComporessGZIP(byte[] _bytes)
    {
        using(var memoryStream = new MemoryStream(_bytes))
        {
            using(var deflateStream = new GZipStream(memoryStream, CompressionMode.Decompress))
            {
                using(var reader = new StreamReader(deflateStream))
                {
                    return reader.ReadToEnd();
                }
            }
        }
    }
}