Get HTTP response header by name. If header doesn't exists, null is returned.
Example: `$request->GetHeader('Content-Type'); // returns 'text/plain; charset=utf-8'`
@param string $name
@return string|NULL
763179
public function GetHeader ($name) {
		return isset($this->headers[$name]) 
			? $this->headers[$name] 
			: NULL;
	}
1278644
public function getHeader($name)
    {
        if (array_key_exists($name, $this->headers)) {
            return $this->headers[$name];
        }
        return null;
    }
1206724
public function get(string $name)
    {
        return isset($this->headers[$name]) ? $this->headers[$name] : null;
    }
270871
public function SayHello($name=null){
		$name=utf8_decode($name);// Because a string parameter may be UTF-8 encoded...
		if($name=='')
			$name='unknown';
		return utf8_encode('Hello '.$name.'!');// Because a string return value should by UTF-8 encoded...
	}
1299503
public String getHeader(String name) {
		if(name == null) {
			throw new NullPointerException("header name is null");
		}
		try {
			return RFC2396UrlDecoder.decode(((javax.sip.address.SipURI) super.uri).getHeader(name));
		} catch (NullPointerException e) {
			return null;
		}
	}
222637
public final function getHeaderLine($name): string
   {
       $key = $this->parseHeaderName($name);
       return array_key_exists($key, $this->header)
            ? implode(",", $this->header[$key])
            : "";
   }
97054
public function get_header($name, $raw = false)
    {
        if (empty($this->headers)) {
            return null;
        }

        return $this->headers->get($name, !$raw);
    }
997570
public String header(Header name) {
		if(null == name) {
			return null;
		}
		return header(name.toString());
	}
551287
public function getHeaderLine($name)
    {
        $internalName = strtolower($name);
        return (true === isset($this->headers[$internalName])) ? implode(',', $this->headers[$internalName]) : '';
    }
1274902
public function getHeader($name)
    {
        if (!$this->hasHeader($name)) {
            throw new \InvalidArgumentException(sprintf('The request header "%s" does not exist.', $name));
        }

        return $this->headers[$name];
    }
85263
public function getHeader($name)
    {
        $headerName = strtoupper(preg_replace("/[^a-zA-Z0-9_]/", '_', $name));
        return filter_input(INPUT_SERVER, 'HTTP_' . $headerName, FILTER_SANITIZE_SPECIAL_CHARS);
    }
124185
public function getHeader($name)
    {
        $key = strtolower($name);

        if (isset($this->responseHeader[$key])) {
            if (!isset($this->responseHeader[$key]['name']) &&
                 is_array($this->responseHeader[$key])) {
                $values = array();

                foreach ($this->responseHeader[$key] as $header) {
                    $values[] = $header['value'];
                }

                return $values;
            } else {
                return $this->responseHeader[$key]['value'];
            }
        }

        return;
    }
1276103
public function getRequestHeader($name)
    {
        return (isset($this->requestHeaders[$name])) ? $this->requestHeaders[$name] : null;
    }
1022241
public String getHeader(String name) {
        name += ":";
        for (String header : headers) {
            if (name.regionMatches(true, 0, header, 0, name.length())) {
                return header.substring(name.length()).trim();
            }
        }
        return null;
    }
682946
public function getHeader($name){
        $headers= $this->getHeaders();
        if(isset($headers[$name])){
            return $headers[$name];
        }else{
            return NULL;
        }
    }
1037556
public function getHeader($name)
    {
        $headers = $this->message->getHeaders();
        return isset($headers[$name]) ? $headers[$name] : null;
    }
301819
@Override
    public String header(String name) {
        List<String> list = request.headers().get(name);
        if (list != null && !list.isEmpty()) {
            return list.get(0);
        }
        return null;
    }