Add header value
If the header already exists data are merged, method DOES NOT replace previous value.

@param string $name  Name of the header.
@param mixed  $value Value of the header can be scalar data type or string.

@return void
501229
public function add($name, $value)
    {
        $name      = $this->normalizeName($name);
        $newValues = is_array($value) ? $value : [$value];
        $data      = [];
        if (isset($this->data[$name])) {
            $data = $this->data[$name];
        }

        $this->data[$name] = array_merge($data, $newValues);
    }
495130
public function addDefaultHeader($name, $value)
    {
        if (!isset($this->headers[$name])) {
            $this->headers[$name] = $value;
        }

        return $this;
    }
1180771
public function append($name, $value)
    {
        $this->list[] = [TypeHinter::to('USVString', $name, 0), TypeHinter::to('USVString', $value, 1)];
        $this->update();
    }
664652
public function addHeader( $name, $value )
	{
		$hs = $this->object->getHeaders();
		$hs->addTextHeader( $name, $value );
		return $this;
	}
303175
public function add(string $name, $value)
    {
        if (in_array($name, ['exp', 'nbf', 'iat']) && is_int($value)) {
            $value = DateTimeImmutable::createFromFormat('U', $value);
        }

        $this->claims[$name] = $value;
    }
1189952
public function addHeader(string $name, string $value = null)
    {
        if (!is_null($value)) {
            return $this->set('headers', $name, $value);
        }

        return $this->set('headers', $name, null);
    }
261392
public function add($name, $value = '')
    {
        Types::assert(['string' => [$name, $value]]);

        $key = strtolower($name);
        if ( ! array_key_exists($key, $this->headers))
        {
            $this->headers[$key] = [];
        }

        $this->headers[$key][] = HeaderFactory::build($name, $value);
    }
224542
public function addHeader($name, $value, $replace = false)
    {
        if ($name == '' || $value == '') return;
        $name = $this->normalizeHeaderName($name);
        $this->headers[] = array('name' => $name, 'value' => $value, 'replace' => $replace);
    }
676975
def add_header(self, name, value):
        '''
        '''
        if self.headers is None:
            self.headers = []
        self.headers.append(dict(Name=name, Value=value))
1349825
protected function addHeader(string $name, string $value) : self
    {
        $this->headers[$name] = $value;

        return $this;
    }
876160
protected function addHeader($name, $value)
    {
        $name  = $this->prepareHeaderName($name);
        $value = $this->prepareHeaderValue($value);

        $normalized = strtolower($name);
        if (! isset($this->headerNames[$normalized])) {
            $this->headerNames[$normalized] = $name;
        }

        $header = $this->headerNames[$normalized];

        if (isset($this->rawHeaders[$header])) {
            $this->rawHeaders[$header] = array_merge(
                $this->rawHeaders[$header],
                $value
            );

            return $this;
        }
        $this->rawHeaders[$header] = $value;

        return $this;
    }
97029
public function addHeader(string $name, $value)
    {
        parent::addHeader($name, $value);

        if (\stripos($name, "cookie") === 0) {
            $this->setCookiesFromHeaders();
        }
    }
256493
public function add(string $name, string $value): void
	{
		$this->headers[$this->normalizeName($name)] = $value;
	}
930504
protected function addOption($name, $value)
    {
        $this->baseload['options'] = array_merge($this->baseload['options'], [$name => $value]);
    }
1282481
protected function addHeader(string $name, $value): Headers
    {
        if (!is_scalar($value) && !is_array($value)) {
            throw new IllegalHeaderValueException($value);
        }

        if (is_scalar($value)) {
            $this->addHeaderValue($name, $value);

            return $this;
        }

        foreach ($value as $item) {
            $this->addHeaderValue($name, $item);
        }

        return $this;
    }
651246
public function withAddedHeader($name, $value): self
    {
        $request = clone $this;
        $request->headers->set($name, $value, false);

        return $request;
    }
1225676
public function changeHeader(string $name, string $value): void
    {
        // if (!array_key_exists($name, $this->headers)) {
            // throw new NotFoundException();
        // }
        $this->headers[$name] = $value;
    }