deasync: deasync hangs in an asynchronous context

When using a deasynced function in asynchronous code, deasync hangs and never returns.

var deasync = require('deasync');

function async(cb) {
  setTimeout(function() {
    cb(null, 'value');
  }, 0);
}

function sync() {
  return deasync(async)();
}

console.log('start', sync());
async(function(err, val) {
  console.log('async result', val);
  console.log(sync());
  console.log('done');
});

Notice that when run, the second call to sync hangs. I was originally using promises when testing this and derived the previous code from this:

var Promise = require('q');
var deasync = require('deasync');

function async() {
  return Promise.resolve('value');
}

function sync() {
  var result, done;
  async().then(function(response) {
    result = response;
  }).finally(function() {
    done = true;
  });

  deasync.loopWhile(function() { return !done; });

  return result;
}

console.log('start', sync());
async().then(function(result) {
  console.log('async result', result);
  return sync();
}).then(function(value) {
  console.log(value);
  console.log('done');
});

I also tried the above example using the Bluebird promise library and ended up with the same results. In the promise example, adding a console.log inside the loopWhile handler shows that it is stuck checking done since the promise chain never completes.