/**
  * build list of variable names and values
  *
  * @param array $arrayVars            
  * @return string
  */
 public static function arrayVarsToString($arrayVars = array())
 {
     $output = "";
     foreach ($arrayVars as $key => $var) {
         $output .= $key . " => " . logger::toString($var) . "\n";
     }
     return $output;
 }