C# DeflateStream WriteAsync(Byte[], Int32, Int32)

[ComVisibleAttribute(false)]//from   w  w w .j a va  2  s. c  om
[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public Task WriteAsync(
  byte[] buffer,
  int offset,
  int count
)

//from w w w.j  a v a2  s . c o m
using System;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.IO;

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private async void Button_Click(object sender, RoutedEventArgs e)
    {
        UnicodeEncoding uniencoding = new UnicodeEncoding();
        string filename = @"c:\Users\exampleuser\Documents\userinputlog.txt";

        byte[] result = uniencoding.GetBytes(UserInput.Text);

        using (FileStream SourceStream = File.Open(filename, FileMode.OpenOrCreate))
        {
            SourceStream.Seek(0, SeekOrigin.End);
            await SourceStream.WriteAsync(result, 0, result.Length);
        }
    }
}