BufferedStream is a class in the System.IO namespace of the C# programming language that provides a way to read and write data to a stream efficiently. It works by using a buffer, which temporarily stores data in memory, reducing the number of read and write operations. This can significantly improve performance, especially when dealing with large amounts of data. When you use a BufferedStream, it wraps around another stream, such as a FileStream or NetworkStream. This allows you to perform operations on the underlying stream while benefiting from the speed of buffered I/O. It is particularly useful in scenarios where data is read or written in small chunks.