function parseActiveBufferViews(bufferViewHeaders, buffersU8) {
  const bufferViewsU8 = {};
  for (let i = 0; i < bufferViewHeaders.length; i++) {
    const bufferViewHeader = bufferViewHeaders[i];

    if (!bufferViewHeader.isActive) {
      continue;
    }

    const start = bufferViewHeader.byteOffset;
    const end = start + bufferViewHeader.byteLength;
    const buffer = buffersU8[bufferViewHeader.buffer];
    const bufferView = buffer.subarray(start, end);
    bufferViewsU8[i] = bufferView;
  }
  return bufferViewsU8;
}
Go through the list of buffer views, and if they are marked as active,
extract a subarray from one of the active buffers.

@param {BufferViewHeader[]} bufferViewHeaders
@param {object} buffersU8 A dictionary of buffer index to a Uint8Array of its contents.
@returns {object} A dictionary of buffer view index to a Uint8Array of its contents.
@private