function getWhitePixelBillboard(billboardCollection, labelCollection) {
  const billboardTexture = labelCollection._backgroundBillboardTexture;
  if (!billboardTexture.hasImage) {
    const canvas = document.createElement("canvas");
    canvas.width = whitePixelSize.x;
    canvas.height = whitePixelSize.y;

    const context2D = canvas.getContext("2d");
    context2D.fillStyle = "#fff";
    context2D.fillRect(0, 0, canvas.width, canvas.height);

    billboardTexture.loadImage(whitePixelCanvasId, canvas);
    billboardTexture.addImageSubRegion(
      whitePixelCanvasId,
      whitePixelBoundingRegion,
    );
  }

  const billboard = billboardCollection.add({
    collection: labelCollection,
  });

  billboard.setImageTexture(billboardTexture);

  return billboard;
}
Create the background image and start loading it into a texture
@private
@param {BillboardCollection} billboardCollection
@param {LabelCollection} labelCollection
@returns {Billboard}