public function testFromStringRoundTripNormalized()
 {
     $hl = HeaderList::fromString('(request-target) Accept');
     $this->assertEquals('(request-target) accept', $hl->string());
 }
 /**
  * @return HeaderList
  *
  * @throws Exception
  */
 private function headerList()
 {
     return HeaderList::fromString($this->parameter('headers'));
 }