value, (stream and resource)

<?php
class Animal{
  public function __construct(){
    $this->created=time();
    $this->logfile_handle=fopen('log.txt','w');
  }
  public function __destruct(){
    fclose($this->logfile_handle);
  }
}

$c=new Animal();

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Running this code in a debugger,
in the constructor
$this->logfile value=2, type=stream
in the destructor
$this->logfile value=2, type=resource

why value =2
what is the difference between stream and resource