An array pool that returns the exact array size requested. I never ended up using this but I'd like to keep this somewhere.

ExactArrayPool.cs

	public class ExactArrayPool<T> : ArrayPool<T>
	{
		public static ArrayPool<T> Shared { get; } = new ExactArrayPool<T>();
		
		private readonly Dictionary<int, Queue<T[]>> _pools = new Dictionary<int, Queue<T[]>>();

		[Pure]
		private Queue<T[]> GetOrCreatePool(int minimumLength)
		{
			if (this._pools.TryGetValue(minimumLength, out Queue<T[]> pool))
				return pool;

			pool = new Queue<T[]>();
			this._pools.Add(minimumLength, pool);
			return pool;
		}
		
		public override T[] Rent(int minimumLength)
		{
			Queue<T[]> pool = GetOrCreatePool(minimumLength);
			if (pool.TryDequeue(out T[] array))
				return array;
			
			return new T[minimumLength];
		}

		public override void Return(T[] array, bool clearArray = false)
		{
			if (clearArray)
			{
				for (int i = 0; i < array.Length; i++)
				{
					array[i] = default;
				}
			}

			Queue<T[]> pool = GetOrCreatePool(array.Length);
			pool.Enqueue(array);
		}
	}