[deltaci]

but it makes function calls, it's not neglectable as it's called as many time as the bytes the file has

[withinboredom]

That’s the api provided, and part of the point. The other option is to read the buffer directly, but it isn’t exposed to the programmer.

[h3h3]

the overload is right below it

  int StreamReader.Read()
  int StreamReader.Read(char[] buffer, int index, int count)

https://github.com/dotnet/runtime/blob/1ba0394d71a4ea6bee7f6...

[deltaci]

You just need to do File.OpenRead instead of OpenText to get a FileStream, then you can read the buffer