Why does a memorystream work and a RecyclableMemoryStream not?

[Sicos1977]

When running the code like this it will return an array that is filled

        public static byte[] DataContractSerializerToDeflatedByteArray(string xml)
        {
            using (var memoryStream = new MemoryStream())
            {
                using (var deflateStream = new DeflateStream(memoryStream, CompressionMode.Compress))
                {
                    var bytes = Encoding.UTF8.GetBytes(xml);
                    deflateStream.Write(bytes, 0, bytes.Length);
                }

                return memoryStream.ToArray();
            }
        }

When running it as this the array always has a length of 0

        public static byte[] DataContractSerializerToDeflatedByteArray(string xml)
        {
            using (var memoryStream = StreamHelpers.Manager.GetStream("Serialization.DataContractSerializerToDeflatedByteArray"))
            {
                using (var deflateStream = new DeflateStream(memoryStream, CompressionMode.Compress))
                {
                    var bytes = Encoding.UTF8.GetBytes(xml);
                    deflateStream.Write(bytes, 0, bytes.Length);
                    deflateStream.Flush();
                    return memoryStream.ToArray();
                }
            }
        }

And running it like this it always gives a already disposed exception

        public static byte[] DataContractSerializerToDeflatedByteArray(string xml)
        {
            using (var memoryStream = StreamHelpers.Manager.GetStream("Serialization.DataContractSerializerToDeflatedByteArray"))
            {
                using (var deflateStream = new DeflateStream(memoryStream, CompressionMode.Compress))
                {
                    var bytes = Encoding.UTF8.GetBytes(xml);
                    deflateStream.Write(bytes, 0, bytes.Length);
                    deflateStream.Flush();
                }

                return memoryStream.ToArray();
            }
        }

[Sicos1977]

The StreamHelpers class

    public static class StreamHelpers
    {
        #region Consts
        private const int BlockSize = 1024;
        private const int LargeBufferMultiple = 1024 * 1024;
        private const int MaxBufferSize = 16 * LargeBufferMultiple;
        #endregion

        #region Fields
        private static RecyclableMemoryStreamManager _manager;
        #endregion

        #region Properties
        /// <summary>
        /// https://github.com/microsoft/Microsoft.IO.RecyclableMemoryStream
        /// </summary>
        public static RecyclableMemoryStreamManager Manager
        {
            get
            {
                if (_manager != null)
                    return _manager;

                _manager = new RecyclableMemoryStreamManager(BlockSize, LargeBufferMultiple, MaxBufferSize)
                {
                    //_manager.GenerateCallStacks = true;
                    AggressiveBufferReturn = false,
                    MaximumFreeLargePoolBytes = MaxBufferSize * 4,
                    MaximumFreeSmallPoolBytes = 100 * BlockSize
                };

                return _manager;
            }
        }
        #endregion
    }

[Sicos1977]

Never mind it is fixed, seems that I have to leave the memorystream open like this

        public static byte[] DataContractSerializerToDeflatedByteArray(string xml)
        {
            using (var memoryStream = StreamHelpers.Manager.GetStream("Serialization.DataContractSerializerToDeflatedByteArray"))
            {
                using (var deflateStream = new DeflateStream(memoryStream, CompressionMode.Compress, true))
                {
                    var bytes = Encoding.UTF8.GetBytes(xml);
                    deflateStream.Write(bytes, 0, bytes.Length);
                }

                return memoryStream.ToArray();
            }
        }