public static function buildSignature($consumerSecret, $tokenSecret, $httpMethod, $url, $oAuthOptions, &$debugInfo = array())
 {
     $requestSignerDebugInfo = array();
     $base_string = RequestSigner::getSignatureBaseString($httpMethod, $url, $oAuthOptions, $requestSignerDebugInfo);
     $requestSignerDebugInfo['signature_base_string'] = $base_string;
     $debugInfo['request_signer'] = $requestSignerDebugInfo;
     $key_parts = array($consumerSecret, $tokenSecret);
     $key_parts = Util::urlencode_rfc3986($key_parts);
     $key = implode('&', $key_parts);
     return base64_encode(hash_hmac('sha1', $base_string, $key, true));
 }