System.Net.NetworkInformation.TeredoHelper.UnsafeNotifyStableUnicastIpAddressTable C# (CSharp) Method

        public static bool UnsafeNotifyStableUnicastIpAddressTable(Action<object> callback, object state)
        {
            if (callback == null)
            {
                NetEventSource.Fail(null, "UnsafeNotifyStableUnicastIpAddressTable called without specifying callback!");
            }

            TeredoHelper helper = new TeredoHelper(callback, state);

            uint err = Interop.IpHlpApi.ERROR_SUCCESS;
            SafeFreeMibTable table = null;

            lock (s_pendingNotifications)
            {
                // If OnAppDomainUnload gets the lock first, tell our caller that we'll finish async.  Their AppDomain 
                // is about to go down anyways.  If we do, hold the lock until we've added helper to the 
                // s_pendingNotifications list (if we're going to complete asynchronously).
                if (Environment.HasShutdownStarted)
                {
                    return false;
                }

                err = Interop.IpHlpApi.NotifyStableUnicastIpAddressTable(AddressFamily.Unspecified,
                    out table, helper._onStabilizedDelegate, IntPtr.Zero, out helper._cancelHandle);

                if (table != null)
                {
                    table.Dispose();
                }

                if (err == Interop.IpHlpApi.ERROR_IO_PENDING)
                {
                    if (helper._cancelHandle.IsInvalid)
                    {
                        NetEventSource.Fail(null, "CancelHandle invalid despite returning ERROR_IO_PENDING");
                    }

                    // Async completion: add us to the s_pendingNotifications list so we'll be canceled in the
                    // event of an AppDomain unload.
                    s_pendingNotifications.Add(helper);
                    return false;
                }
            }

            if (err != Interop.IpHlpApi.ERROR_SUCCESS)
            {
                throw new Win32Exception((int)err);
            }

            return true;
        }

        public override UnicastIPAddressInformationCollection GetUnicastAddresses()
        {
            // Wait for the Address Table to stabilize
            using (ManualResetEvent stable = new ManualResetEvent(false)) {
                if (!TeredoHelper.UnsafeNotifyStableUnicastIpAddressTable(StableUnicastAddressTableCallback, stable))
                {
                    stable.WaitOne();
                }
            }

            return(GetUnicastAddressTable());
        }