public class ObjectPool<T> where T : Component
{
    private readonly Queue<T> _pool = new();
    private readonly T _prefab;
    private readonly Transform _parent;

    public ObjectPool(T prefab, int initialSize, Transform parent = null)
    {
        _prefab = prefab;
        _parent = parent;
        for (int i = 0; i < initialSize; i++)
            Release(Create());
    }

    public T Get()
    {
        T obj = _pool.Count > 0 ? _pool.Dequeue() : Create();
        obj.gameObject.SetActive(true);
        return obj;
    }

    public void Release(T obj)
    {
        obj.gameObject.SetActive(false);
        _pool.Enqueue(obj);
    }

    private T Create() => Object.Instantiate(_prefab, _parent);
}

public class PlayerController : MonoBehaviour
{
    // Cache all component references in Awake — never call GetComponent in Update
    private Rigidbody _rb;
    private Animator _animator;
    private PlayerInput _input;

    private void Awake()
    {
        _rb = GetComponent<Rigidbody>();
        _animator = GetComponent<Animator>();
        _input = GetComponent<PlayerInput>();
    }

    private void FixedUpdate()
    {
        // Use cached references; use deltaTime for frame-independence
        Vector3 move = _input.MoveDirection * (speed * Time.fixedDeltaTime);
        _rb.MovePosition(_rb.position + move);
    }
}

public abstract class State
{
    public abstract void Enter();
    public abstract void Tick(float deltaTime);
    public abstract void Exit();
}

public class StateMachine
{
    private State _current;

    public void TransitionTo(State next)
    {
        _current?.Exit();
        _current = next;
        _current.Enter();
    }

    public void Tick(float deltaTime) => _current?.Tick(deltaTime);
}

// Usage example
public class IdleState : State
{
    private readonly Animator _animator;
    public IdleState(Animator animator) => _animator = animator;
    public override void Enter() => _animator.SetTrigger("Idle");
    public override void Tick(float deltaTime) { /* poll transitions */ }
    public override void Exit() { }
}