public function update($key, $value)
    {
        if (!empty($this->get($this->normalizeKey($key)))) {
            $this->headers[$this->normalizeKey($key)] = $value;
        }
    }
public function update($key, $value)
    {
        if (!empty($this->get($this->normalizeKey($key)))) {
            $this->headers[$this->normalizeKey($key)] = $value;
        }
    }
public function update ( $ key , $ value ) { if ( ! empty ( $ this -> get ( $ this -> normalizeKey ( $ key ) ) ) ) { $ this -> headers [ $ this -> normalizeKey ( $ key ) ] = $ value ; } }
Update existing header.

@param (string) $key   The header key
@param (string) $value The new header value

@since 3.0.0

@return void
Update existing header .