System.Threading.RegisteredWaitHandle.Unregister C# (CSharp) Method

        public bool Unregister(System.Threading.WaitHandle waitObject)
        {
            throw null;
        }

        internal static async Task <bool> WaitOneAsync(
            this WaitHandle handle, int millisecondsTimeout, CancellationToken cancellationToken = default)
        {
            var tcs = new TaskCompletionSource <bool>();

            using var tokenRegistration =
                      cancellationToken.Register(state => ((TaskCompletionSource <bool>)state !).TrySetCanceled(), tcs);

            RegisteredWaitHandle?registeredHandle = null;

            try
            {
                registeredHandle = ThreadPool.RegisterWaitForSingleObject(
                    handle,
                    (state, timedOut) => ((TaskCompletionSource <bool>)state !).TrySetResult(!timedOut),
                    state: tcs,
                    millisecondsTimeout,
                    executeOnlyOnce: true);
                return(await tcs.Task);
            }
            finally
            {
                registeredHandle?.Unregister(null);
            }
        }