Eu estava olhando a documentação da microsoft e vi que eles chamam o StreamReader sem o FileStream. Assim me pergunto qual a necessidade do FileStream?
Link aqui: https://docs.microsoft.com/en-us/dotnet/standard/io/how-to-read-text-from-a-file
using System;
using System.IO;
class Program
{
public static void Main()
{
try
{
// Open the text file using a stream reader.
using (var sr = new StreamReader("TestFile.txt"))
{
// Read the stream as a string, and write the string to the console.
Console.WriteLine(sr.ReadToEnd());
}
}
catch (IOException e)
{
Console.WriteLine("The file could not be read:");
Console.WriteLine(e.Message);
}
}
}