code: function Loader (options) {
    // var self = this
  
    typeforce({
      keeper: 'Object',
      networkName: 'String',
      prefix: 'String'
    }, options)
  
    typeforce({
      put: 'Function',
      getMany: 'Function'
    }, options.keeper)
  
    // Transform.call(this, {
    //   objectMode: true,
    //   highWaterMark: 16
    // })
  
    utils.bindPrototypeFunctions(this)
  
    extend(this, options)
    if (options.lookup) this.lookupWith(options.lookup)
  }
docs: inherits(Loader, Transform) 
  Load data from the chain (blockchain + keeper)
  @param {Function} lookup (optional) - function to look up identities by fingerprints
  @param {BitKeeper|BitKeeper client} keeper
  @param {String} networkName
  @param {String} prefix - prefix for OP_RETURN data
  @param {Object} options