AnimeTask.cs

using System;
using System.Threading.Tasks;
using AnimeTask;
using UnityEngine;
using Animator = AnimeTask.Animator;

public class Hoge : MonoBehaviour
{
    public async void Start()
    {
        Debug.Log("Move Start");
        await Anime.Play(
            Translate.LocalPosition(transform),
            new Vector3(-5f, 0f, 0f),
            new Vector3(5f, 0f, 0f),
            Animator.Uniform(TimeSpan.FromSeconds(2f))
        );
        Debug.Log("Move End");
    }
}


namespace AnimeTask
{
    public static class Anime
    {
        public static Task Play<T>(ITranslator<T> translator, T start, T end, IAnimator<T> animator)
        {
            var now = animator.Update(start, end);
            translator.Update(now);
            return Task.CompletedTask;
        }
    }

    public interface IAnimator<T>
    {
        T Update(T start, T end);
    }

    public static class Animator
    {
        public static IAnimator<Vector3> Uniform(TimeSpan duration)
        {
            return new UniformAnimator();
        }

        public class UniformAnimator : IAnimator<Vector3>
        {
            public Vector3 Update(Vector3 start, Vector3 end)
            {
                return start;
            }
        }
    }

    public interface ITranslator<in T>
    {
        void Update(T value);
    }

    public static class Translate
    {
        public static ITranslator<Vector3> LocalPosition(Transform transform)
        {
            return new PositionTranslator(transform);
        }

        public class PositionTranslator : ITranslator<Vector3>
        {
            private readonly Transform transform;

            public PositionTranslator(Transform transform)
            {
                this.transform = transform;
            }

            public void Update(Vector3 value)
            {
                transform.localPosition = value;
            }
        }
    }
}