setTrackVolume ({ state, dispatch }, { track, volume }) {
      const trackData = state.tracks[track]
      if (!trackData) {
        throw new Error('Invalid track specified')
      }

      const volumes = Array.from(trackData.keys())
        .map(id => dispatch('setSoundVolume', { id, volume }))

      return Promise.all(volumes)
    }
Sets volume of specified track

@param opts {object}
@param opts.track {string} track to adjust volume of
@param opts.volume {number} volume between 0 and 1

@return Array of IDs that volume was set on

@throws {Error} when invalid track specified