Asynchronous Process, Multi threading or Multitasking in Codeigniter PHP

<?php

class Mylibrary
{

public function __construct()
{
$this->ci =& get_instance();
}

function do_in_background($url, $params)
{
$post_string = http_build_query($params);
$parts = parse_url($url);
$errno = 0;
$errstr = "";

//Use SSL & port 443 for secure servers
//Use otherwise for localhost and non-secure servers
//For secure server
$fp = fsockopen('ssl://' . $parts['host'], isset($parts['port'])
? $parts['port'] : 443, $errno, $errstr, 30);
//For localhost and un-secure server
//$fp = fsockopen($parts['host'], isset($parts['port'])
? $parts['port'] : 80, $errno, $errstr, 30);
if(!$fp)
{
echo "Some thing Problem";
}
$out = "POST ".$parts['path']." HTTP/1.1\r\n";
$out.= "Host: ".$parts['host']."\r\n";
$out.= "Content-Type: application/x-www-form-urlencoded\r\n";
$out.= "Content-Length: ".strlen($post_string)."\r\n";
$out.= "Connection: Close\r\n\r\n";
if (isset($post_string)) $out.= $post_string;
fwrite($fp, $out);
fclose($fp);
}
}
?>

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Test extends CI_Controller {

/**
* load list modal and helpers
*/
function __Construct(){
parent::__Construct();
$this->load->helper(array('form', 'url'));
$this->load->model('test_model');
}

/**
*  @desc : Function to send mail
*  @param :void
*  @return : void
*/
public function sendmail(){
$this->load->library('email');
$user_email  = $_POST['email'];
$message     = "Testing";

$this->email->from('anand.abhay1910@gmail.com', 'Test');
$this->email->to($user_email);
$this->email->subject("test");
$this->email->message($message);
$this->email->send();
}

/**
*  @desc : Function to call insert() method
*  of test_model to insert post data in database
*  @param :void
*  @return : void
*/
public function insert(){
$email = $this->input->post('email');
$name = $this->input->post('name');
$this->test_model->insert($email, $name);
}
}

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Test extends CI_Controller {

/**
* load list modal, library and helpers
*/
function __Construct(){
parent::__Construct();
$this->load->helper(array('form', 'url'));
$this->load->model('test_model');
$this->load->library('mylibrary');
}

/**
*  @desc : Function to perform multiple task in background
*  @param :void
*  @return : void
*/
public  function index(){

$url = base_url()."test/sendmail";
$url1 = base_url()."test/insert";

$param = array('email' => "anand.abhay1910@gmail.com" );
$param1 = array('name' => "Abhay",
'email' => "anand.abhay1910@gmail.com" );

$this->mylibrary->do_in_background($url, $param);
$this->mylibrary->do_in_background($urls, $param1);

}

/**
*  @desc : Function to send mail
*  @param :void
*  @return : void
*/
public function sendmail(){

$this->load->library('email');
$user_email  = $_POST['email'];
$message     = "Testing";

$this->email->from('heyrajcool@gmail.com', 'Around');
$this->email->to($user_email);
$this->email->subject("test");
$this->email->message($message);
$this->email->send();
}

/**
*  @desc : Function to call insert() method
*  of test_model to insert data in database
*  @param :void
*  @return : void
*/
public function insert(){

$email = $this->input->post('email');
$name = $this->input->post('name');
$this->test_model->insert($email, $name);
}
}