addCustomHeadersMiddleware,
	// The generic tracer needs to be the first middleware to catch all requests
	// returned early by any other middleware (but after the middleware that
	// sets the amz request id).
	httpTracerMiddleware,
	// Auth middleware verifies incoming authorization headers and routes them
	// accordingly. Client receives a HTTP error for invalid/unsupported
	// signatures.
	//

	op = strings.Replace(op, "-fm", "", 1)
	return op
}

// If trace is enabled, execute the request if it is traced by other handlers
// otherwise, generate a trace event with request information but no response.
func httpTracerMiddleware(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Setup a http request response recorder - this is needed for
		// http stats requests and audit if enabled.