public function addHeader($header, $value = NULL)
	{
		if($header instanceof HttpHeaderInterface)
		{
			$n = strtolower($header->getFieldName());
			
			if(empty($this->headers[$n]))
			{
				$this->headers[$n] = [[(string)$header->getFieldName(), trim($header->getFieldValue())]];
			}
			else
			{
				$this->headers[$n][] = [(string)$header->getFieldName(), trim($header->getFieldValue())];
			}
		}
		else
		{
			$n = strtolower($header);
			
			if(empty($this->headers[$n]))
			{
				$this->headers[$n] = [[(string)$header, trim($value)]];
			}
			else
			{
				$this->headers[$n][] = [(string)$header, trim($value)];
			}
		}
		
		return $this;
	}