function getContentEntityId(subtree, implicitCoordinates, contentIndex) {
  const metadataTables = subtree._contentMetadataTables;
  if (!defined(metadataTables)) {
    return undefined;
  }

  const metadataTable = metadataTables[contentIndex];
  if (!defined(metadataTable)) {
    return undefined;
  }

  const availability = subtree._contentAvailabilityBitstreams[contentIndex];
  const tileIndex = subtree.getTileIndex(implicitCoordinates);
  if (availability.getBit(tileIndex)) {
    const contentJumpBuffer = subtree._contentJumpBuffers[contentIndex];
    return contentJumpBuffer[tileIndex];
  }

  return undefined;
}
Get the entity ID for a content within this subtree.
@param {ImplicitSubtree} subtree The subtree
@param {ImplicitTileCoordinates} implicitCoordinates The global coordinates of a content
@param {number} contentIndex The content index, for distinguishing between multiple contents.
@return {number} The entity ID for this content for accessing content metadata, or <code>undefined</code> if not applicable.

@private