public static function headerStringToArray($str){

		if(!\is_string($str)){
			throw new \InvalidArgumentException('$str not a string');
		}

		$arr = array();
		$header = '';

		foreach(\explode("\r\n", \trim($str)) as $hStr){
			
			$header = \explode(':', $hStr, 2);
			
			if(\strlen($hStr >= 3)){ //[h]:[v], min 3
				$arr[\strtolower(\trim($header[0]))] 
						= isset($header[1]) ? \trim($header[1]) : null;
			}
			
		}

		return $arr;

	}