Unity : How to write by appending to binary Files using FileStreams ?

WritingToBinaryFilesAppend.cs

using System.IO;

using (var fileStream = new FileStream(file_path, FileMode.Append, FileAccess.Write, FileShare.None))
using (var bw = new BinaryWriter(fileStream))
{
    bw.Write(0.0f);
    
    byte[] lotsOfData;
    bw.Write(lotsOfData);
}