Rented

Rented.cs

public interface IRented<T> : IDisposable
{
	Memory<T> Memory { get; }
	Span<T> Span { get; }
}

public static class ArrayPoolExtensions
{
	public static IRented<T> GetRented<T>(this ArrayPool<T> pool, int minimumLength, bool clearOnReturn = false)
	{
		ArgumentNullException.ThrowIfNull(pool);
		ArgumentOutOfRangeException.ThrowIfNegativeOrZero(minimumLength);
		return new Rented<T>(pool, minimumLength, clearOnReturn);
	}

	private sealed class Rented<T>(ArrayPool<T> pool, int minimumLength, bool clearOnReturn = false) : IRented<T>
	{
		private T[]? buffer = pool.Rent(minimumLength);
		private T[] GetBuffer() => buffer ?? throw new ObjectDisposedException(GetType().Name);

		public Memory<T> Memory => GetBuffer().AsMemory(0, minimumLength);
		public Span<T> Span => GetBuffer().AsSpan(0, minimumLength);

		~Rented() => Dispose();

		public void Dispose()
		{
			if (buffer is not { } toReturn)
				return;
			GC.SuppressFinalize(this);
			ArrayPool<T>.Shared.Return(toReturn, clearOnReturn);
			buffer = null;
		}
	}
}