CielaSpike.Task.OnMoveNext C# (CSharp) Method

        private bool OnMoveNext()
        {
            // no running for null;
            if (_innerRoutine == null)
                return false;

            // set current to null so that Unity not get same yield value twice;
            Current = null;

            // loops until the inner routine yield something to Unity;
            while (true)
            {
                // a simple state machine;
                switch (_state)
                {
                    // first, goto background;
                    case RunningState.Init:
                        GotoState(RunningState.ToBackground);
                        break;
                    // running in background, wait a frame;
                    case RunningState.RunningAsync:
                        return true;

                    // runs on main thread;
                    case RunningState.RunningSync:
                        MoveNextUnity();
                        break;

                    // need switch to background;
                    case RunningState.ToBackground:
                        GotoState(RunningState.RunningAsync);
                        // call the thread launcher;
                        MoveNextAsync();
                        return true;

                    // something was yield returned;
                    case RunningState.PendingYield:
                        if (_pendingCurrent == Ninja.JumpBack)
                        {
                            // do not break the loop, switch to background;
                            GotoState(RunningState.ToBackground);
                        }
                        else if (_pendingCurrent == Ninja.JumpToUnity)
                        {
                            // do not break the loop, switch to main thread;
                            GotoState(RunningState.RunningSync);
                        }
                        else
                        {
                            // not from the Ninja, then Unity should get noticed,
                            // Set to Current property to achieve this;
                            Current = _pendingCurrent;

                            // yield from background thread, or main thread?
                            if (_previousState == RunningState.RunningAsync)
                            {
                                // if from background thread, 
                                // go back into background in the next loop;
                                _pendingCurrent = Ninja.JumpBack;
                            }
                            else
                            {
                                // otherwise go back to main thread the next loop;
                                _pendingCurrent = Ninja.JumpToUnity;
                            }

                            // end this iteration and Unity get noticed;
                            return true;
                        }
                        break;

                    // done running, pass false to Unity;
                    case RunningState.Done:
                    case RunningState.CancellationRequested:
                    default:
                        return false;
                }
            }
        }