WebClient.DownloadDataAsync замораживает мой UI

есть в моей форме конструктора, после InitializeComponent следующего кода:WebClient.DownloadDataAsync замораживает мой UI

using (WebClient client = new WebClient()) 
{ 
    client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted); 
    client.DownloadDataAsync("http://example.com/version.txt"); 
}

Когда я начинаю свою форму, пользовательский интерфейс не появляется до client_DownloadDataCompleted приподнят. Метод client_DownloadDataCompleted пуст, поэтому проблем нет.

Что я делаю неправильно? Как это сделать, не замораживая пользовательский интерфейс?

Спасибо за ваше время.
С уважением.

ПОЛНЫЙ КОД:

Program.cs

using System; 
using System.Windows.Forms; 

namespace Lala 
{ 
    static class Program 
    { 
     /// <summary> 
     /// The main entry point for the application. 
     /// </summary> 
     [STAThread] 
     static void Main() 
     { 
      Application.EnableVisualStyles(); 
      Application.SetCompatibleTextRenderingDefault(false); 
      Application.Run(new Form1()); 
     } 
    } 
}

Form1.cs

using System; 
using System.Net; 
using System.Windows.Forms; 

namespace Lala 
{ 
    public partial class Form1 : Form 
    { 
     WebClient client = new WebClient(); 

     public Form1() 
     { 
      client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted); 
      client.DownloadDataAsync(new Uri("http://www.google.com")); 
      InitializeComponent(); 
     } 

     void client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e) 
     { 
      textBox1.Text += "A"; 
     } 
    } 

    partial class Form1 
    { 
     /// <summary> 
     /// Required designer variable. 
     /// </summary> 
     private System.ComponentModel.IContainer components = null; 

     /// <summary> 
     /// Clean up any resources being used. 
     /// </summary> 
     /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param> 
     protected override void Dispose(bool disposing) 
     { 
      if (disposing && (components != null)) 
      { 
       components.Dispose(); 
      } 
      base.Dispose(disposing); 
     } 

     #region Windows Form Designer generated code 

     /// <summary> 
     /// Required method for Designer support - do not modify 
     /// the contents of this method with the code editor. 
     /// </summary> 
     private void InitializeComponent() 
     { 
      this.button1 = new System.Windows.Forms.Button(); 
      this.textBox1 = new System.Windows.Forms.TextBox(); 
      this.SuspendLayout(); 
      // 
      // button1 
      // 
      this.button1.Location = new System.Drawing.Point(12, 12); 
      this.button1.Name = "button1"; 
      this.button1.Size = new System.Drawing.Size(75, 23); 
      this.button1.TabIndex = 0; 
      this.button1.Text = "button1"; 
      this.button1.UseVisualStyleBackColor = true; 
      // 
      // textBox1 
      // 
      this.textBox1.Location = new System.Drawing.Point(12, 41); 
      this.textBox1.Multiline = true; 
      this.textBox1.Name = "textBox1"; 
      this.textBox1.Size = new System.Drawing.Size(468, 213); 
      this.textBox1.TabIndex = 1; 
      // 
      // Form1 
      // 
      this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); 
      this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; 
      this.ClientSize = new System.Drawing.Size(492, 266); 
      this.Controls.Add(this.textBox1); 
      this.Controls.Add(this.button1); 
      this.Name = "Form1"; 
      this.Text = "Form1"; 
      this.ResumeLayout(false); 
      this.PerformLayout(); 

     } 

     #endregion 

     private System.Windows.Forms.Button button1; 
     private System.Windows.Forms.TextBox textBox1; 
    } 
}

WebClient.DownloadDataAsync замораживает мой UI

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