Initial QSfera import

Server/pkg/middleware/throttle.go

@@ -0,0 +1,19 @@
+package middleware
+
+import (
+	"net/http"
+
+	"github.com/go-chi/chi/v5/middleware"
+)
+
+// Throttle limits the number of concurrent requests.
+func Throttle(limit int) func(http.Handler) http.Handler {
+	if limit > 0 {
+		return middleware.Throttle(limit)
+	}
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			next.ServeHTTP(w, r)
+		})
+	}
+}