code: function setSegment(start, end, identifier) {
      if (identifier === undefined || identifier === null || identifier.length === 0) {
        identifier = "default";
      }
  
      this.segments[identifier] = new WaveformDataSegment(this, start, end);
  
      return this.segments[identifier];
    }
docs: Creates a new segment of data.
  Pretty handy if you need to bookmark a duration and display it according
  to the current offset.
  
  ```javascript
  var waveform = WaveformData.create({ ... });
  
  console.log(Object.keys(waveform.segments));          // -> []
  
  waveform.set_segment(10, 120);
  waveform.set_segment(30, 90, "speakerA");
  
  console.log(Object.keys(waveform.segments));          // -> ['default', 'speakerA']
  console.log(waveform.segments.default.min.length);    // -> 110
  console.log(waveform.segments.speakerA.min.length);   // -> 60
  ```
  
  @param {Integer} start Beginning of the segment (inclusive)
  @param {Integer} end Ending of the segment (exclusive)
  @param {String*} identifier Unique identifier. If nothing is specified,
  *default* will be used as a value.
  @return {WaveformDataSegment}