function findKeyframeIndex(keyframe, keyframeNodes) {
  scratchBinarySearchKeyframeNode.keyframe = keyframe;
  return binarySearch(
    keyframeNodes,
    scratchBinarySearchKeyframeNode,
    KeyframeNode.searchComparator,
  );
}
Find the index of a given key frame position within an array of KeyframeNodes,
or the complement (~) of the index where it would be in the sorted array.
@param {number} keyframe
@param {KeyframeNode[]} keyframeNodes
@returns {number}
@private