text: import Box from '../box'
  Box.smhd = function (data, output) {
    let stream = this.stream
    stream.writeUint8(data.version)
    stream.writeUint24(data.flag)
    let balance = data.balance.split('.')
    stream.writeUint8(balance[0])
    stream.writeUint8(balance[1])
    stream.fill(2)
    output.write(new Uint8Array(stream.buffer.slice(0, stream.position)))
    if (stream.position !== data.size - 8) {
      throw new Error(`${data.type} box incomplete`)
    } else {
      this.outputSize = stream.position
    }
    delete this.data
  }
  