constructor({height, width, x, y}: SizeAndPositionInfo) {
    this.height = height;
    this.width = width;
    this.x = x;
    this.y = y;

    this._indexMap = {};
    this._indices = [];
  }
A section of the Window.
Window Sections are used to group nearby cells.
This enables us to more quickly determine which cells to display in a given region of the Window.
Sections have a fixed size and contain 0 to many cells (tracked by their indices).