_getLabelCapacity(exampleTime) {
    const timeOpts = this.options.time;
    const displayFormats = timeOpts.displayFormats;

    // pick the longest format (milliseconds) for guesstimation
    const format = displayFormats[timeOpts.unit] || displayFormats.millisecond;
    const exampleLabel = this._tickFormatFunction(exampleTime, 0, ticksFromTimestamps(this, [exampleTime], this._majorUnit), format);
    const size = this._getLabelSize(exampleLabel);
    // subtract 1 - if offset then there's one less label than tick
    // if not offset then one half label padding is added to each end leaving room for one less label
    const capacity = Math.floor(this.isHorizontal() ? this.width / size.w : this.height / size.h) - 1;
    return capacity > 0 ? capacity : 1;
  }
@param {number} exampleTime
@return {number}
@private