message: test: verify that ready() is called
diff: @@ -2,7 +2,15 @@ var tape = require('tape')
  var blake2b = require('./')
  var vectors = require('blake2b/test-vectors.json')
  +var readyCalled = false
  +process.on('exit', function () {
  + if (!readyCalled)
  + throw new Error('ready not called')
  +})
  +
  blake2b.ready(function () {
  + readyCalled = true
  +
  tape('hello world', function (t) {
  var hash = blake2b()
  .update(Buffer.from('hello'))
  