source: binary-improvements/7dtd-server-fixes/src/PersistentData/Player.cs@ 458

using System;
using UnityEngine;

namespace AllocsFixes.PersistentData {
        [Serializable]
        public class Player {
                private readonly PlatformUserIdentifierAbs internalId;
                private readonly PlatformUserIdentifierAbs platformId;
                private readonly PlatformUserIdentifierAbs crossPlatformId;
                
                private int entityId;
                private string name;
                private string ip;
                private long totalPlayTime;

                private DateTime lastOnline;

                private Inventory inventory;

                private int lastPositionX, lastPositionY, lastPositionZ;

                private bool chatMuted;
                private int maxChatLength;
                private string chatColor;
                private bool chatName;
                private uint expToNextLevel;
                private int level;

                [NonSerialized] private ClientInfo clientInfo;

                public PlatformUserIdentifierAbs InternalId => internalId;
                public PlatformUserIdentifierAbs PlatformId => platformId;
                public PlatformUserIdentifierAbs CrossPlatformId => crossPlatformId;

                public int EntityID => entityId;

                public string Name => name ?? string.Empty;

                public string IP => ip ?? string.Empty;

                public Inventory Inventory => inventory ??= new Inventory ();

                public bool IsOnline => clientInfo != null;

                public ClientInfo ClientInfo => clientInfo;

                public EntityPlayer Entity => IsOnline ? GameManager.Instance.World.Players.dict [clientInfo.entityId] : null;

                public long TotalPlayTime {
                        get {
                                if (IsOnline) {
                                        return totalPlayTime + (long) (DateTime.Now - lastOnline).TotalSeconds;
                                }

                                return totalPlayTime;
                        }
                }

                public DateTime LastOnline => IsOnline ? DateTime.Now : lastOnline;

                public Vector3i LastPosition => IsOnline ? new Vector3i (Entity.GetPosition ()) : new Vector3i (lastPositionX, lastPositionY, lastPositionZ);

                public bool LandProtectionActive =>
                        GameManager.Instance.World.IsLandProtectionValidForPlayer (GameManager.Instance
                                .GetPersistentPlayerList ().GetPlayerData (InternalId));

                public float LandProtectionMultiplier =>
                        GameManager.Instance.World.GetLandProtectionHardnessModifierForPlayer (GameManager.Instance
                                .GetPersistentPlayerList ().GetPlayerData (InternalId));

                public float Level {
                        get {
                                float expForNextLevel =
                                        (int) Math.Min (Progression.BaseExpToLevel * Mathf.Pow (Progression.ExpMultiplier, level + 1),
                                                int.MaxValue);
                                float fLevel = level + 1f - expToNextLevel / expForNextLevel;
                                return fLevel;
                        }
                }

                public bool IsChatMuted {
                        get => chatMuted;
                        set => chatMuted = value;
                }

                public int MaxChatLength {
                        get {
                                if (maxChatLength == 0) {
                                        maxChatLength = 255;
                                }

                                return maxChatLength;
                        }
                        set => maxChatLength = value;
                }

                public string ChatColor {
                        get {
                                if (string.IsNullOrEmpty (chatColor)) {
                                        chatColor = "";
                                }

                                return chatColor;
                        }

                        set => chatColor = value;
                }

                public bool ChatName {
                        get => chatName;
                        set => chatName = value;
                }

                public Player (PlatformUserIdentifierAbs _internalId, PlatformUserIdentifierAbs _platformId, PlatformUserIdentifierAbs _crossPlatformId) {
                        internalId = _internalId;
                        platformId = _platformId;
                        crossPlatformId = _crossPlatformId;
                        inventory = new Inventory ();
                }

                public void SetOffline () {
                        if (clientInfo == null) {
                                return;
                        }

                        Log.Out ($"Player set to offline: {InternalId}");
                        lastOnline = DateTime.Now;
                        try {
                                Vector3i lastPos = new Vector3i (Entity.GetPosition ());
                                lastPositionX = lastPos.x;
                                lastPositionY = lastPos.y;
                                lastPositionZ = lastPos.z;
                                totalPlayTime += (long) (Time.timeSinceLevelLoad - Entity.CreationTimeSinceLevelLoad);
                        } catch (NullReferenceException) {
                                Log.Out ("Entity not available. Something seems to be wrong here...");
                        }

                        clientInfo = null;
                }

                public void SetOnline (ClientInfo _ci) {
                        Log.Out ($"Player set to online: {InternalId}");
                        clientInfo = _ci;
            entityId = _ci.entityId;
                        name = _ci.playerName;
                        ip = _ci.ip;
                        lastOnline = DateTime.Now;
                }

                public void Update (ClientInfo _clientInfo, PlayerDataFile _pdf) {
                        UpdateProgression (_clientInfo, _pdf);
                        inventory.Update (_pdf);
                }

                private void UpdateProgression (ClientInfo _clientInfo, PlayerDataFile _pdf) {
                        if (_pdf.progressionData.Length <= 0) {
                                return;
                        }

                        if (!GameManager.Instance.World.Entities.dict.TryGetValue (_clientInfo.entityId, out Entity entity)) {
                                return;
                        }

                        if (entity is not EntityPlayer ep) {
                                return;
                        }

                        expToNextLevel = (uint)ep.Progression.ExpToNextLevel;
                        level = ep.Progression.Level;
                }

        }
}