PHP dio_write() function close after sending - php

Question

I am trying to send data to my serial port using the php_dio.dll extention below code manage to send "HELLO WORLD" to serial com port 11 (com11) and returned the bytes, now i cannot close the serial port after it received my data.
On my com11 i have an arduino mega attached.
PHP code
$portName = '\\\\.\COM11';
$baudRate = 9600;
$bits = 8;
$spotBit = 1;
header( 'Content-type: text/plain; charset=utf-8' );
?>
Serial Port Test
================
<?php
function echoFlush($string)
{
echo $string . "\n";
flush();
ob_flush();
}
if(!extension_loaded('dio'))
{
echoFlush( "PHP Direct IO does not appear to be installed for more info see: http://www.php.net/manual/en/book.dio.php" );
exit;
}
try
{
//the serial port resource
$bbSerialPort;
echoFlush( "Connecting to serial port: {$portName}" );
if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN')
{
$bbSerialPort = dio_open($portName, O_RDWR );
//we're on windows configure com port from command line
exec("mode {$portName} baud={$baudRate} data={$bits} stop={$spotBit} parity=n xon=on");
}
else //'nix
{
$bbSerialPort = dio_open($portName, O_RDWR | O_NOCTTY | O_NONBLOCK );
dio_fcntl($bbSerialPort, F_SETFL, O_SYNC);
//we're on 'nix configure com from php direct io function
dio_tcsetattr($bbSerialPort, array(
'baud' => $baudRate,
'bits' => $bits,
'stop' => $spotBit,
'parity' => 0
));
}
if(!$bbSerialPort)
{
echoFlush( "Could not open Serial port {$portName} ");
exit;
}
// send data
$dataToSend = "HELLO WORLD!";
echoFlush( "Writing to serial port data: \"{$dataToSend}\"" );
$bytesSent = dio_write($bbSerialPort, $dataToSend );
echoFlush( "Sent: {$bytesSent} bytes" );
//date_default_timezone_set ("Europe/London");
$runForSeconds = new DateInterval("PT10S"); //10 seconds
$endTime = (new DateTime())->add($runForSeconds);
echoFlush( "Waiting for {$runForSeconds->format('%S')} seconds to recieve data on serial port" );
while (new DateTime() < $endTime) {
$data = dio_read($bbSerialPort, 256); //this is a blocking call
if ($data) {
echoFlush( "Data Recieved: ". $data );
}
}
echoFlush( "Closing Port" );
dio_close($bbSerialPort);
}
catch (Exception $e)
{
echoFlush( $e->getMessage() );
exit(1);
}
Arduino Code
char incomingByte;
void setup() {
Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
}
void loop() {
// send data only when you receive data:
if (Serial.available() > 0) {
// read the incoming byte:
incomingByte = Serial.read();
// say what you got:
Serial.print("I received: ");
Serial.println(incomingByte);
}
}