请教这段代码cluster worker和net模块一起使用为何会出现阻塞？

很神奇的是，在master里直接调用socketHandler的话ab测试下不会阻塞

在worker里调用，ab测试并发数为1的时候不会阻塞

但像下面这样写，ab测试

ab -n 10 -c 2 http://localhost:10086

请求直接就阻塞了。。。

var net = require('net');
var http = require('http');
var cluster = require('cluster');

var recevice_socket_count = 0;
var recevice_http_count = 0;

var httpServer = http.createServer(function(req,res){
    console.log('recevice_http_count',++recevice_http_count);
    res.write('wow');
    res.end();
});

function socketHandler(socket){
  console.log('recevice_socket_count',++recevice_socket_count);
  socket.readable = socket.writeable = true;
  httpServer.emit('connection',socket);
  socket.emit('connect');
}


if(cluster.isMaster){
  var worker = cluster.fork();
  net.createServer(function(socket){
    worker.send("socket", socket);
    //socketHandler(socket);
  }).listen(10086, function() {
    console.log('netServer bound');
  });
}else{

  cluster.worker.on("message", function(data, socket) {
        socketHandler(socket);
  });
}