old_contents: var crypto = require('crypto')
  
  var exportFn = require('./pbkdf2')
  var exported = exportFn(crypto)
  
  module.exports = {
    pbkdf2: exported.pbkdf2,
    pbkdf2Sync: exported.pbkdf2Sync,
  
    // for crypto-browserify
    __pbkdf2Export: exportFn
  }
  
new_contents: var crypto = require('crypto')
  
  var exportFn = require('./pbkdf2')
  var exported = exportFn(crypto)
  
  module.exports = {
    pbkdf2: exported.pbkdf2,
    pbkdf2Sync: exported.pbkdf2Sync
  }
  
subject: remove unnecessary __pbkdf2Export