Ergo\Http\HeaderField::fromString PHP Метод

    public static function fromString($headerString)
    {
        $headerString = trim($headerString);
        list($name, $value) = explode(': ', trim($headerString), 2);
        return new self($name, $value);
    }

 /**
  * Adds an HTTP header to all requests
  * @param mixed either a string or a HeaderField
  * @return $this
  */
 public function addHeader($header)
 {
     if (is_string($header)) {
         $header = HeaderField::fromString($header);
     }
     $this->headers[] = $header;
     return $this;
 }