DuplexTextStream combined FileStream, StreamWriter and StreamReader in one class.

DuplexTextStream

using System;
using System.Diagnostics;
using System.IO;

namespace EFLFE
{
    [DebuggerDisplay("DuplexTextStream: {FileName}")]
    public sealed class DuplexTextStream : FileStream
    {
        // What? Single Responsibility Principle? I don't understand what you're talking about.
        public readonly StreamWriter In;
        public readonly StreamReader Out;

        public readonly string FileName;
        public readonly string FilePath;

        public DuplexTextStream(string filePath) : base(filePath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.Read)
        {
            FileName = Path.GetFileName(filePath);
            FilePath = filePath;

            In = new StreamWriter(this);
            Out = new StreamReader(this);
        }

        [Obsolete("Use CloseDuplex.", true)]
        public new void Close() { }

        public void CloseDuplex()
        {
            In.Close();
            Out.Close();
            base.Close();
        }

        public bool IsEmpty => Length == 0L;

        public bool EndOfStream => Position >= Length;

        public void SeekToEnd() => Position = Length;

    }
}