   config:
     debug: true
     output: "mbtiles"
-
     maxZoom: 14
-    copyAboveZoom: null
 
   queueSize: 64
 

          stream.pause()
          paused = true

        promise = if @config.copyAboveZoom and z >= @config.copyAboveZoom
          @_loadTile z, x, y
          .then (buffer) => @_storeTile z, x, y, buffer
        else
          @_processTile z, x, y

        promise.finally =>
          queueSpots++
          if paused and queueSpots > 0
            stream.resume()

    @protobuf = new Protobuf fs.readFileSync __dirname+"/../proto/vector_tile.desc"

  grind: (source, @destination, @callback) ->
    @_log "[>] starting to grind #{source} into #{@destination}"

    @_mustExist source
    .then => @_loadMBTiles source
