IJSONsavable.cs

using System.Collections.Generic;
using System.Reflection;
using System.Linq;
using System.IO;
using System;
using Newtonsoft.Json;
using UnityEngine;
using static CommunicationEvents;


// I would go for static virtual methods, but C#9 does not allow me...
// static methods cannot be overwritten -> virtual
public interface IJSONsavable<T> where T : IJSONsavable<T>, new()
{
    // stand-in for non static methods
    public static readonly IJSONsavable<T> Instance = new T();

    public static readonly FieldInfo[] JsonSaveableFields =
    #region one-time-initialisation
         typeof(T)
        .GetFields(
            BindingFlags.Instance |
            BindingFlags.Public |
            BindingFlags.NonPublic |
            BindingFlags.Static)
        .Where((field)
            => !field.GetCustomAttributes().Any((attribute)
                => attribute.GetType() == typeof(JsonIgnoreAttribute))
            && field.FieldType.GetInterfaces().Any((inter)
                => inter.IsGenericType && inter.GetGenericTypeDefinition() == typeof(IJSONsavable<>)))
        .ToArray();
    #endregion one-time-initialisation

    public static readonly FieldInfo[] JsonAutoPreProcessFields =
    #region one-time-initialisation
         typeof(T)
        .GetFields(
            BindingFlags.Instance |
            BindingFlags.Public |
            BindingFlags.NonPublic |
            BindingFlags.Static)
        .Where((field)
            => !field.GetCustomAttributes().Any((attribute)
                => attribute.GetType() == typeof(JsonIgnoreAttribute))
            && field.GetCustomAttributes().Any((attribute)
                => attribute.GetType() == typeof(JSONsavable.JsonAutoPreProcessAttribute))
            && field.FieldType.GetInterfaces().Any((inter)
                => inter.IsGenericType && inter.GetGenericTypeDefinition() == typeof(IJSONsavable<>)))
        .ToArray();
    #endregion one-time-initialisation

    public static readonly FieldInfo[] JsonAutoPostProcessFields =
    #region one-time-initialisation
         typeof(T)
        .GetFields(
            BindingFlags.Instance |
            BindingFlags.Public |
            BindingFlags.NonPublic |
            BindingFlags.Static)
        .Where((field)
            => !field.GetCustomAttributes().Any((attribute)
                => attribute.GetType() == typeof(JsonIgnoreAttribute))
            && field.GetCustomAttributes().Any((attribute)
                => attribute.GetType() == typeof(JSONsavable.JsonAutoPostProcessAttribute))
            && field.FieldType.GetInterfaces().Any((inter)
                => inter.IsGenericType && inter.GetGenericTypeDefinition() == typeof(IJSONsavable<>)))
        .ToArray();
    #endregion one-time-initialisation

    public static readonly FieldInfo[] JsonSeperateFields =