node.js extension causing a segmentation fault

helloworld.cc

#include <v8.h>
#include <node.h>
#include <node_events.h>
#include <boost/thread.hpp>
#include <boost/bind.hpp>

#include <iostream>

using namespace node;
using namespace v8;
using namespace boost;

class HelloWorld : public EventEmitter
{ 
private:
  ev_async * completed_;
  
public:
  static void Init(Handle<Object> target)
  {
    HandleScope scope;
    Local<FunctionTemplate> t = FunctionTemplate::New(New);
    t->Inherit(EventEmitter::constructor_template);
    t->InstanceTemplate()->SetInternalFieldCount(1);
    NODE_SET_PROTOTYPE_METHOD(t, "trigger", Trigger);
    target->Set(String::NewSymbol("HelloWorld"), t->GetFunction());
  }
  
  static void Complete(EV_P_ ev_async * w, int revents)
  {
    HelloWorld * hw = static_cast<HelloWorld *>(w->data);
    hw->Emit(String::New("ping"), 0, NULL);
  }
  
  HelloWorld()
  {
    completed_ = new ev_async();
  }
  
  ~HelloWorld()
  {
    ev_async_stop(EV_DEFAULT_UC_ completed_);
    delete completed_;
  }

private:
  static Handle<Value> New(const Arguments& args)
  {
    HandleScope scope;
    HelloWorld * hw = new HelloWorld();
    hw->completed_->data = hw;
  	ev_async_init(hw->completed_, HelloWorld::Complete);
  	ev_async_start(EV_DEFAULT_UC_ hw->completed_);
  	ev_unref(EV_DEFAULT_UC);
  	hw->Wrap(args.This());
    return args.This();
  }

  static Handle<Value> Trigger(const Arguments & args)
  {
    HandleScope scope;
    HelloWorld * hw = ObjectWrap::Unwrap<HelloWorld>(args.This());
    thread t(bind(& HelloWorld::threadFunc, hw));
    return Undefined();
  }
  
  void threadFunc()
  {
    HandleScope scope;
    sleep(0);
    ev_async_send(EV_DEFAULT_UC_ completed_);
  }
};

extern "C" {
  static void init(Handle<Object> target)
  {
    HandleScope scope;
    HelloWorld::Init(target);
  }
  NODE_MODULE(helloworld, init);
}

test.js

var sys = require('sys');
var hello = require('./build/default/helloworld');

var hi = new hello.HelloWorld();
hi.addListener('ping', function () {
  sys.puts('pong');
});
hi.trigger();

var http = require('http');
http.createServer(function (req, res) {
  res.end('Hello World\n');
}).listen(8124, "127.0.0.1");
sys.puts('Server running at http://127.0.0.1:8124/');

wscript

def set_options(opt):
  opt.tool_options("compiler_cxx")

def configure(conf):
  conf.check_tool("compiler_cxx")
  conf.check_tool("node_addon")

def build(bld):
  obj = bld.new_task_gen("cxx", "shlib", "node_addon")
  obj.cxxflags = ["-g", "-D_FILE_OFFSET_BITS=64", "-D_LARGEFILE_SOURCE", "-Wall"]
  obj.target = "helloworld"
  obj.source = "helloworld.cc"
  obj.includes = ["../../boost/include/"]
  obj.lib = ["boost_thread"]