CacheBehaviour alternative

ComponentCache.cs

using UnityEngine;
using System.Collections.Generic;

public class ComponentCache
{ 
    public enum LogMessageLevel { all, error, none}
    LogMessageLevel logMessageLevel = LogMessageLevel.error;

    private GameObject _gameObject;
    private List<Component> _components = new List<Component>();
    public ComponentCache(GameObject gameObject)
    {
        _gameObject = gameObject;
    }

    public ComponentCache(GameObject gameObject , LogMessageLevel messageLevel)
    {
        _gameObject = gameObject;
        logMessageLevel = messageLevel;
    }

    public T GetComponent<T>() where T : Component
    {
        for (int i = 0; i < _components.Count; i++)
        {
            if (_components[i].GetType() == typeof(T))
            {
                Log(typeof(T).Name + " found in cache.");
                return _components[i] as T;
            }
        }

        Component c = _gameObject.GetComponent<T>();
        if (c != null)
        {
            Log(typeof(T).Name + " added to cache.");
            _components.Add(c);
            return c as T;
        }

        LogError(typeof(T).Name + " not found.");
        return null;
    }

    public void DestroyAllComponentsOfType<T>() where T : Component
    {
        bool destroyed = false;
        for (int i = 0; i < _components.Count; i++)
        {
            if (_components[i].GetType() == typeof(T))
            {
                Log(typeof(T).Name + " removed from cache and destroyed.");
                Object.DestroyImmediate(_components[i]);
                _components.RemoveAt(i);
                destroyed = true;
            }
        }

        if (!destroyed)
            LogError(typeof(T).Name + " not found.");
    }

    public void DestroyComponent(Component component)
    {
        bool destroyed = false;
        for (int i = 0; i < _components.Count; i++)
        {
            if (_components[i] == component)
            {
                Log(component.GetType().Name + " removed from cache and destroyed.");
                Object.DestroyImmediate(_components[i]);
                _components.RemoveAt(i);
                destroyed = true;
            }
        }

        if (!destroyed)
            LogError(component.GetType().Name + " not found.");
    }

    void Log(string message)
    {
        if (logMessageLevel == LogMessageLevel.all)
            Debug.Log(message);
    }

    void LogError(string message)
    {
        if (logMessageLevel != LogMessageLevel.none)
            Debug.LogError(message);
    }
}

// Test Case
/*
using UnityEngine;
using UnityEngine.Assertions;

public class TestCacheComponent : MonoBehaviour
{
    public ComponentCache cc;
    AudioSource asrc1;
    void Start()
    {
        cc = new ComponentCache(gameObject , ComponentCache.LogMessageLevel.all);

        Debug.LogWarning("Test Cache");
        cc.GetComponent<AudioSource>();
        cc.GetComponent<AudioSource>();
        cc.DestroyAllComponentsOfType<AudioSource>();
        

        Debug.LogWarning("Add component test");
        asrc1 = gameObject.AddComponent<AudioSource>();
        asrc1.mute = true;
        AudioSource testAs = cc.GetComponent<AudioSource>();
        if (testAs != asrc1)
            Debug.LogError("Retrieved component not the same?");
        
        testAs = cc.GetComponent<AudioSource>();
        if (testAs != asrc1)
            Debug.LogError("Retrieved component not the same?");
        
        
        Debug.LogWarning("Adding second component");
        AudioSource asrc2 = gameObject.AddComponent<AudioSource>();
        Debug.LogWarning("Destroying first component");
        cc.DestroyComponent(asrc1);
        cc.GetComponent<AudioSource>();
        cc.GetComponent<AudioSource>();

        Assert.IsNull(asrc1);
        Assert.IsNotNull(asrc2);
        

    }
    bool doOnce = true;
    void Update()
    {
        if (doOnce && asrc1 == null)
        {
            doOnce = false;
            Debug.LogWarning("AudioSource 1 is now null");
        }
    }
}
*/

Why you didn't use hashtable? Getting records from it much more quicker than from List.
And what about cases, when GameObject has more than one component of particular type?