Converting APM patterns into tasks

The legacy APM approach used the IAsyncResult interface to create asynchronous methods with a design pattern using two methods: BeginMethodName and EndMethodName. Let's try to understand the journey of a program from being synchronous, to an APM, and then to a task.

Here is a synchronous method that reads data from a text file:

private static void ReadFileSynchronously()        
{            
    string path = @"Test.txt";
    //Open the stream and read content.
    using (FileStream fs = File.OpenRead(path))
    {
         byte[] b = new byte[1024];
         UTF8Encoding encoder = new UTF8Encoding(true);
         fs.Read(b, 0, b.Length);
         Console.WriteLine(encoder.GetString(b));
     }
 }

There is nothing fancy in the preceding code. First, we created a FileStream object and called the Read method, which reads the file from the disk...