//optimized serialization
public void WriteToStream(Stream stream)
{
using (var writer = new BinaryWriter(stream))
{
writer.Write(string.IsNullOrEmpty(UserName) ? "" : UserName);
writer.Write(ExpirationTime.ToBinary());
writer.Write((uint)PermissionsToken);
writer.Write(string.IsNullOrEmpty(Cookie) ? "" : Cookie);
writer.Write(string.IsNullOrEmpty(ImpersonatedUserName) ? "" : ImpersonatedUserName);
}
}
