According to MSDN in .Net 4.5 System.IO.Compression is based on zlib.
I am trying now to change my current interop based reading from a zlib deflated stream from a non .
Here's a revised version of ProVega's answer, which inflates the byte array into a string:
using (var stream = new MemoryStream(bytes,2, bytes.Length - 2))
using (var inflater = new DeflateStream(stream, CompressionMode.Decompress))
using (var streamReader = new StreamReader(inflater))
{
return streamReader.ReadToEnd();
}