public static function id($id = null) {
		if ($id) {
			static::$id = $id;
			session_id(static::$id);
		}
		if (static::started()) {
			return session_id();
		}
		return static::$id;
	}
public static function id($id = null) {
		if ($id) {
			static::$id = $id;
			session_id(static::$id);
		}
		if (static::started()) {
			return session_id();
		}
		return static::$id;
	}
public static function id ( $ id = null ) { if ( $ id ) { static :: $ id = $ id ; session_id ( static :: $ id ) ; } if ( static :: started ( ) ) { return session_id ( ) ; } return static :: $ id ; }
Returns the session id.
Calling this method will not auto start the session. You might have to manually
assert a started session.

Passing an id into it, you can also replace the session id if the session
has not already been started.
Note that depending on the session handler, not all characters are allowed
within the session id. For example, the file session handler only allows
characters in the range a-z A-Z 0-9 , (comma) and - (minus).

@param string|null $id Id to replace the current session id
@return string Session id
Returns the session id . Calling this method will not auto start the session . You might have to manually assert a started session .