code: public function signRequestHeaders(
  		$httpVerb = 'GET',
  		$path = '/',
  		$query = array(),
  		$headers = null,
  		$forTableStorage = false,
  		$resourceType = Storage::RESOURCE_UNKNOWN,
  		$requiredPermission = CredentialsAbstract::PERMISSION_READ,
  		$rawData = null
  	) {
  	    return $headers;
  	}
docs: Sign request with credentials
  
  @param string $httpVerb HTTP verb the request will use
  @param string $path Path for the request
  @param array $query Query arguments for the request (key/value pairs)
  @param array $headers x-ms headers to add
  @param boolean $forTableStorage Is the request for table storage?
  @param string $resourceType Resource type
  @param string $requiredPermission Required permission
  @param mixed  $rawData Raw post data
  @return array Array of headers