code: function MatrixUser(userId, data, escape=true) {
      if (!userId) {
          throw new Error("Missing user_id");
      }
      if (data && Object.prototype.toString.call(data) !== "[object Object]") {
          throw new Error("data arg must be an Object");
      }
      this.userId = userId;
      const split = this.userId.split(":");
      this.localpart = split[0].substring(1);
      this.host = split[1];
      if (escape) {
          this.escapeUserId();
      }
      this._data = data || {};
  }
docs: Construct a Matrix user.
  @constructor
  @param {string} userId The user_id of the user.
  @param {Object=} data Serialized data values
  @param {boolean} escape [true] Escape the user's localpart.