コルーチンを使用して Swoole で同時実行性の高い swoole_pop3 関数を実装する方法

<?php

function swoole_pop3($host, $port, $username, $password, $callback)
{
    $server = new SwooleServer($host, $port, SWOOLE_BASE, SWOOLE_SOCK_TCP);
    
    $server->on('receive', function($server, $fd, $reactor_id, $data) use ($username, $password, $callback) {
        $pop3 = new POP3($username, $password);
        
        $response = $pop3->command($data);
        
        $server->send($fd, $response);
        
        if ($response == "+OK conection closed") {
            $server->close($fd);
            
            $callback();
        }
    });
    
    $server->start();
}

class POP3
{
    private $username;
    private $password;
    private $connected = false;
    private $command_history = array();

    function __construct($username, $password)
    {
        $this->username = $username;
        $this->password = $password;
    }

    function command($command_str)
    {
        $command = $this->parse_command($command_str);

        $command_name = strtoupper($command['name']);
        $command_args = isset($command['args']) ? $command['args'] : array();

        if ($command_name == "USER") {
            $username = $command_args[0];
            if ($username == $this->username) {
                return "+OK Password required 
";
            } else {
                return "-ERR User not found 
";
            }
        } elseif ($command_name == "PASS") {
            $password = $command_args[0];
            if ($password == $this->password) {
                $this->connected = true;
                return "+OK connected 
";
            } else {
                return "-ERR Password incorrect 
";
            }
        } else {
            return "-ERR command not supported 
";
        }
    }

    function parse_command($command_str)
    {
        $command_str = trim($command_str);
        $command = array();

        $name_end_pos = strpos($command_str, ' ');

        if ($name_end_pos === false) {
            $command['name'] = $command_str;
        } else {
            $command['name'] = substr($command_str, 0, $name_end_pos);
            $args_str = substr($command_str, $name_end_pos);
            $args = explode(' ', $args_str);
            $args = array_filter($args);
            $command['args'] = $args;
        }
        return $command;
    }
}

<?php

use SwooleCoroutineChannel;

function coroutine_pop3($count)
{
    $chan = new Channel($count);

    for ($i = 0; $i < $count; $i++) {
        go(function() use ($i, $chan)
        {
            swoole_pop3('127.0.0.1', 9999, 'username', 'password', function() use ($i, $chan) {
                $chan->push($i);
            });
        });
    }

    for ($i = 0; $i < $count; $i++) {
        $chan->pop();
    }
}