- makes regex static for performance

Signed-off-by: Vincent Biret <[email protected]>

Author: baywet

src/Microsoft.OpenApi/Validations/Rules/OpenApiPathsRules.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
+using System;
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
 using Microsoft.OpenApi.Models;
@@ -35,21 +36,21 @@ public static class OpenApiPathsRules
                     }
                 });
 
+        private static readonly Regex regexPath = new Regex("\\{([^/]+)\\}", RegexOptions.Compiled, TimeSpan.FromMilliseconds(100));
         /// <summary>
         /// A relative path to an individual endpoint. The field name MUST begin with a slash.
         /// </summary>
         public static ValidationRule<OpenApiPaths> PathMustBeUnique =>
             new ValidationRule<OpenApiPaths>(
                 (context, item) =>
                 {
-                    const string regexPath = "\\{([^/]+)\\}";
                     var hashSet = new HashSet<string>();
 
                     foreach (var path in item.Keys)
                     {
                         context.Enter(path);
 
-                        var pathSignature = Regex.Replace(path, regexPath, "{}");
+                        var pathSignature = regexPath.Replace(path, "{}");
 
                         if (!hashSet.Add(pathSignature))
                             context.CreateError(nameof(PathMustBeUnique),