Suggested improvement for Guid serialization

[natilivni]

I noticed that in the IAsyncBinaryWriter/IAsyncBinaryReader implementation Guids are serialized using the ToString method.

I think it would be both faster and would take less storage to use the ToByteArray method instead.

[sakno]

Writer/reader supports both ways: raw binary and formatted. Use WriteAsync<T>(T, CancellationToken) to write a value of arbitrary blittable type.

[natilivni]

Problem with that is that I believe the Guid structure is not garuanteed to be the same in all platforms.

[sakno]

It has 16 byte length on all platforms, you can check Remarks section for this type. The only potential problem here is endianess of bytes. However, x86_64 as well as x86 arch are little-endian.

Anyway, it's easy to add conversion for endianess to ensure consistency:

using System;
using DotNext.Runtime;

Guid value = Guid.NewGuid();
if (!BitConverter.IsLittleEndian)
  Intrinsics.Reverse(ref value);

Alternative approach is to use WriteAsync(ReadOnlyMemory<byte> input, LengthFormat? lengthFormat = null, CancellationToken token = default):

Guid value = Guid.NewGuid();
await writer.WriteAsync(value.ToByteArray().AsMemory(), null, token);

I would rather not use this approach because ToByteArray allocates the copy on the heap.