UnityEditor.SessionState.GetString C# (CSharp) Method

        internal static extern string GetString(string key, string defaultValue);
        internal static Vector3 GetVector3(string key, Vector3 defaultValue)

        public void DeserializeState(string uid)
        {
            m_bFilterSelection    = SessionState.GetBool(uid + Styles.serializeFilterSelection, false);
            m_ShowInactiveObjects = SessionState.GetBool(uid + Styles.showInactiveObjects, false);

            MultiColumnHeaderState headerState = new MultiColumnHeaderState(multiColumnHeader.state.columns);
            string columnHeaderState           = EditorPrefs.GetString(uid + Styles.serializeColumnHeaderState, "");

            if (!string.IsNullOrEmpty(columnHeaderState))
            {
                JsonUtility.FromJsonOverwrite(columnHeaderState, headerState);
            }

            if (MultiColumnHeaderState.CanOverwriteSerializedFields(headerState, multiColumnHeader.state))
            {
                Column.OverwriteSerializedFields(headerState, multiColumnHeader.state);
            }

            for (int i = 0; i < multiColumnHeader.state.columns.Length; i++)
            {
                var filter = Col(i).filter;
                if (filter == null)
                {
                    continue;
                }

                string filterState = SessionState.GetString(uid + Styles.serializeFilter + i, null);
                if (string.IsNullOrEmpty(filterState))
                {
                    continue;
                }

                filter.DeserializeState(filterState);
            }

            string treeViewState = SessionState.GetString(uid + Styles.serializeTreeViewState, "");

            if (!string.IsNullOrEmpty(treeViewState))
            {
                JsonUtility.FromJsonOverwrite(treeViewState, state);
            }
        }