Added loopUntilNoEvents() API to wait for aribtrary code.

 * Existing APIs rely on explicit callback argument or predicate.
   This API does not require such prior information, just like
   how the nodejs main loop continues or terminates.

 * To use this API to block for a specific region of code, you should
   take care of other existing callbacks using unref() and ref() methods
   to prevent them from making loopUntilNoEvents() to block "longer"
   than you want.

index.js

@@ -65,6 +65,11 @@
 		process._tickDomainCallback();
 		binding.run();
 	};
+
+	module.exports.loopUntilNoEvents = function(){
+		process._tickDomainCallback();
+		binding.loopUntilNoEvents();
+	};
 
 	module.exports.loopWhile = function(pred){
 	  while(pred()){

src/deasync.cc

@@ -10,8 +10,18 @@ NAN_METHOD(Run) {
   info.GetReturnValue().Set(Nan::Undefined());
 }
 
+NAN_METHOD(LoopUntilNoEvents) {
+  Nan::HandleScope scope;
+  bool more = false;
+  do {
+    more = uv_run(uv_default_loop(), UV_RUN_ONCE);
+  } while (more);
+  info.GetReturnValue().Set(Nan::Undefined());
+}
+
 static NAN_MODULE_INIT(init) {
   Nan::Set(target, Nan::New("run").ToLocalChecked(), Nan::GetFunction(Nan::New<FunctionTemplate>(Run)).ToLocalChecked());
+  Nan::Set(target, Nan::New("loopUntilNoEvents").ToLocalChecked(), Nan::GetFunction(Nan::New<FunctionTemplate>(LoopUntilNoEvents)).ToLocalChecked());
 }
 
 NODE_MODULE(deasync, init)

test.js

@@ -8,6 +8,10 @@ var sleep = deasync(function (timeout, done) {
   setTimeout(done, timeout);
 });
 
+var sleep_without_cb_or_pred = function (timeout) {
+  setTimeout(function() { console.log('second'); }, timeout);
+};
+
 var request = deasync(function (url, done) {
   http.get(url, function (res) {
     res.on('error', done);
@@ -21,11 +25,22 @@ var request = deasync(function (url, done) {
   }).on('error', done);
 });
 
-
+// Expected order: "first", "second", "third", "async1"
+var t = setTimeout(function () {
+  console.log('async1');
+}, 2000);
+t.unref(); // should not make loopUntilNoEvents() to block
+console.log('first');
+sleep_without_cb_or_pred(1000);
+deasync.loopUntilNoEvents();
+console.log('third');
+t.ref();  // should make loopUntilNoEvents() to block
+deasync.loopUntilNoEvents();
+
+// Expected order: ls -la, "async2", request
 setTimeout(function () {
-  console.log('async');
+  console.log('async2');
 }, 1000);
-
 console.log(exec('ls -la'));
 sleep(2000);
 console.log(request('http://nodejs.org'));