allow retrieving spans from fiber.Ctx

example/main.go

@@ -39,6 +39,12 @@ func main() {
 	}))
 	defer tracing.ShutdownTracer()
 
+	main.Use(func(c *fiber.Ctx) error {
+		span := tracing.SpanFromContext(c)
+		span.AddEvent("pushed into a span an event from middleware")
+		return c.Next()
+	})
+
 	main.Get("/", Handler)
 
 	// handle interrupts (shutdown)