function deltaLengthByteArray(reader, count, output) {
  const lengths = new Int32Array(count)
  deltaBinaryUnpack(reader, count, lengths)
  for (let i = 0; i < count; i++) {
    output[i] = new Uint8Array(reader.view.buffer, reader.view.byteOffset + reader.offset, lengths[i])
    reader.offset += lengths[i]
  }
}
@param {DataReader} reader
@param {number} count
@param {Uint8Array[]} output