code: function Memory (opts) {
    var self = this
    Storage.call(self, opts)
  
    // load this._data
    self.clear()
      .then(function () { self.emit('ready') })
      .catch(function (err) { self.emit('error', err) })
  }
docs: @class Memory
  @extends Storage
  
  @param {Object} [opts]
  @param {string} [opts.networkName=livenet]
  @param {boolean} [opts.compactMode=false]