System.Threading.Barrier.RemoveParticipants C# (CSharp) Method

        public void RemoveParticipants(int participantCount)
        {
            // check dispose
            ThrowIfDisposed();

            // Validate input
            if (participantCount < 1)
            {
                throw new ArgumentOutOfRangeException(nameof(participantCount), participantCount,
                    SR.Barrier_RemoveParticipants_NonPositive_ArgumentOutOfRange);
            }

            // in case of this is called from the PHA
            if (_actionCallerID != 0 && Environment.CurrentManagedThreadId == _actionCallerID)
            {
                throw new InvalidOperationException(SR.Barrier_InvalidOperation_CalledFromPHA);
            }

            SpinWait spinner = new SpinWait();
            while (true)
            {
                int currentTotal = _currentTotalCount;
                int total;
                int current;
                bool sense;
                GetCurrentTotal(currentTotal, out current, out total, out sense);

                if (total < participantCount)
                {
                    throw new ArgumentOutOfRangeException(nameof(participantCount),
                        SR.Barrier_RemoveParticipants_ArgumentOutOfRange);
                }
                if (total - participantCount < current)
                {
                    throw new InvalidOperationException(SR.Barrier_RemoveParticipants_InvalidOperation);
                }
                // If the remaining participats = current participants, then finish the current phase
                int remaingParticipants = total - participantCount;
                if (remaingParticipants > 0 && current == remaingParticipants)
                {
                    if (SetCurrentTotal(currentTotal, 0, total - participantCount, !sense))
                    {
                        FinishPhase(sense);
                        break;
                    }
                }
                else
                {
                    if (SetCurrentTotal(currentTotal, current, total - participantCount, sense))
                    {
                        break;
                    }
                }
                spinner.SpinOnce();
            }
        }

        /// <summary>
        /// Test RemoveParticipants
        /// </summary>
        /// <param name="initialCount">The initial barrier participants count</param>
        /// <param name="participantsToRemove">The aprticipants that will be added</param>
        /// <param name="exceptionType">Type of the exception in case of invalid input, null for valid cases</param>
        /// <returns>Tru if the test succeeded, false otherwise</returns>
        private static bool RunBarrierTest5_RemoveParticipants(int initialCount, int participantsToRemove, Type exceptionType)
        {
            TestHarness.TestLog("RemoveParticipants(" + initialCount + "," + participantsToRemove + ")");
            Barrier b = new Barrier(initialCount);
            Exception exception = null;
            try
            {
                b.RemoveParticipants(participantsToRemove);
                if (b.ParticipantCount != initialCount - participantsToRemove)
                {
                    TestHarness.TestLog("RemoveParticipants failed, total participant was not decreased");
                    return false;
                }

            }
            catch (Exception ex)
            {
                exception = ex;
            }

            if (exception != null && exceptionType == null)
            {
                TestHarness.TestLog("RemoveParticipants failed, unexpected exception has been thrown.");
                return false;
            }
            if (exception != null && !Type.Equals(exceptionType, exception.GetType()))
            {
                TestHarness.TestLog("RemoveParticipants failed, exceptions types do not match.");
                return false;
            }
            TestHarness.TestLog("RemoveParticipants succeeded");
            return true;
        }