function measure(args, callback) {
    typeset({...args, metricsOnly: true}, (result) => {
      const [x0, y0, x1, y1] = result.blockBounds
      callback({
        width: x1 - x0,
        height: y1 - y0
      })
    })
  }
For a given text string and font parameters, determine the resulting block dimensions
after wrapping for the given maxWidth.
@param args
@param callback