Different buffers of bytes. Array, unmanaged heap and memory mapped file implementations.

All of them implement IByteBlock interface:

public interface IByteBlock : IDisposable {
    int Length { get; }
    Span<byte> AsSpan();
    UnmanagedMemoryStream AsStream();
}

Each block provide read/write span or stream.

Each call of AsSpan() or AsStream() produces new one.

NOTE: Due to Span<T> Length property being int, maximum size of any IByteBlock is int.MaxValue : 2 147 483 647 (0x7fffffff).

Backed by array of bytes.

Maximum length of byte[] in C# is 2 147 483 591 (0x7FFFFFC7)

Buffer allocated in heap.

Buffer persisted on file system.

Can be used for fast writing or reading of files smaller than int.MaxValue (2GiB - 1 byte).