System.IO.Compression.DeflateStream.FlushAsync C# (CSharp) Method

        public override Task FlushAsync(CancellationToken cancellationToken)
        {
            EnsureNoActiveAsyncOperation();
            EnsureNotDisposed();

            if (cancellationToken.IsCancellationRequested)
                return Task.FromCanceled(cancellationToken);

            return _mode != CompressionMode.Compress || !_wroteBytes ? Task.CompletedTask : FlushAsyncCore(cancellationToken);
        }

        public void Precancellation()
        {
            var ms = new MemoryStream();

            using (Stream compressor = new DeflateStream(ms, CompressionMode.Compress, leaveOpen: true))
            {
                Assert.True(compressor.WriteAsync(new byte[1], 0, 1, new CancellationToken(true)).IsCanceled);
                Assert.True(compressor.FlushAsync(new CancellationToken(true)).IsCanceled);
            }
            using (Stream decompressor = CreateStream(ms, CompressionMode.Decompress, leaveOpen: true))
            {
                Assert.True(decompressor.ReadAsync(new byte[1], 0, 1, new CancellationToken(true)).IsCanceled);
            }
        }